Auto merge of #21088 - emilio:gecko-sync, r=emilio

style: Import changes from mozilla-central.

See each individual commit for details.

101 files changed, 645 insertions, 640 deletions

diff --git a/components/layout/block.rs b/components/layout/block.rs
index 003f1fb2e02..351b0dba9d9 100644
--- a/components/layout/block.rs
+++ b/components/layout/block.rs
@@ -1417,7 +1417,7 @@ impl BlockFlow {
             // Per CSS 2.1 § 16.3.1, text alignment propagates to all children in flow.
             //
             // TODO(#2265, pcwalton): Do this in the cascade instead.
-            let containing_block_text_align = self.fragment.style().get_inheritedtext().text_align;
+            let containing_block_text_align = self.fragment.style().get_inherited_text().text_align;
             kid.mut_base().flags.set_text_align(containing_block_text_align);
 
             // Handle `text-indent` on behalf of any inline children that we have. This is
@@ -1425,7 +1425,7 @@ impl BlockFlow {
             // we know.
             if kid.is_inline_flow() {
                 kid.as_mut_inline().first_line_indentation =
-                    self.fragment.style().get_inheritedtext().text_indent
+                    self.fragment.style().get_inherited_text().text_indent
                         .to_used_value(containing_block_size);
             }
         }
@@ -2340,7 +2340,7 @@ pub trait ISizeAndMarginsComputer {
                                                         containing_block_inline_size),
                                   MaybeAuto::from_style(position.inline_end,
                                                         containing_block_inline_size),
-                                  style.get_inheritedtext().text_align,
+                                  style.get_inherited_text().text_align,
                                   available_inline_size)
     }
 
diff --git a/components/layout/construct.rs b/components/layout/construct.rs
index efa3ccd176a..063b1ee710f 100644
--- a/components/layout/construct.rs
+++ b/components/layout/construct.rs
@@ -1095,7 +1095,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                         kid_flow.as_block()
                                 .fragment
                                 .style()
-                                .get_inheritedtable()
+                                .get_inherited_table()
                                 .caption_side == side {
                         table_wrapper_flow.add_new_child(kid_flow);
                     }
@@ -1256,7 +1256,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
         // Determine if the table cell should be hidden. Per CSS 2.1 § 17.6.1.1, this will be true
         // if the cell has any in-flow elements (even empty ones!) and has `empty-cells` set to
         // `hide`.
-        let hide = node.style(self.style_context()).get_inheritedtable().empty_cells == EmptyCells::Hide &&
+        let hide = node.style(self.style_context()).get_inherited_table().empty_cells == EmptyCells::Hide &&
             node.children().all(|kid| {
                 let position = kid.style(self.style_context()).get_box().position;
                 !kid.is_content() ||
@@ -1871,7 +1871,7 @@ fn bidi_control_chars(style: &ServoArc<ComputedValues>) -> Option<(&'static str,
     use style::computed_values::unicode_bidi::T::*;
 
     let unicode_bidi = style.get_text().unicode_bidi;
-    let direction = style.get_inheritedbox().direction;
+    let direction = style.get_inherited_box().direction;
 
     // See the table in http://dev.w3.org/csswg/css-writing-modes/#unicode-bidi
     match (unicode_bidi, direction) {
diff --git a/components/layout/display_list/builder.rs b/components/layout/display_list/builder.rs
index 16a1fc85770..d8467958038 100644
--- a/components/layout/display_list/builder.rs
+++ b/components/layout/display_list/builder.rs
@@ -1013,7 +1013,7 @@ impl FragmentDisplayListBuilding for Fragment {
                 id: webrender_image.key.unwrap(),
                 stretch_size: placement.tile_size.to_layout(),
                 tile_spacing: placement.tile_spacing.to_layout(),
-                image_rendering: style.get_inheritedbox().image_rendering.to_layout(),
+                image_rendering: style.get_inherited_box().image_rendering.to_layout(),
             })));
         });
     }
@@ -1581,7 +1581,7 @@ impl FragmentDisplayListBuilding for Fragment {
         display_list_section: DisplayListSection,
         clip: Rect<Au>,
     ) {
-        if self.style().get_inheritedbox().visibility != Visibility::Visible {
+        if self.style().get_inherited_box().visibility != Visibility::Visible {
             return;
         }
 
@@ -1744,7 +1744,7 @@ impl FragmentDisplayListBuilding for Fragment {
                     state,
                     &text_fragment,
                     stacking_relative_content_box,
-                    &self.style.get_inheritedtext().text_shadow.0,
+                    &self.style.get_inherited_text().text_shadow.0,
                     clip,
                 );
 
@@ -1765,7 +1765,7 @@ impl FragmentDisplayListBuilding for Fragment {
                     state,
                     &text_fragment,
                     stacking_relative_content_box,
-                    &self.style.get_inheritedtext().text_shadow.0,
+                    &self.style.get_inherited_text().text_shadow.0,
                     clip,
                 );
 
@@ -1837,7 +1837,7 @@ impl FragmentDisplayListBuilding for Fragment {
                             stretch_size: stacking_relative_content_box.size.to_layout(),
                             tile_spacing: LayoutSize::zero(),
                             image_rendering: self.style
-                                .get_inheritedbox()
+                                .get_inherited_box()
                                 .image_rendering
                                 .to_layout(),
                         })));
@@ -2005,7 +2005,7 @@ impl FragmentDisplayListBuilding for Fragment {
         }
 
         // Create display items for text decorations.
-        let text_decorations = self.style().get_inheritedtext().text_decorations_in_effect;
+        let text_decorations = self.style().get_inherited_text().text_decorations_in_effect;
 
         let logical_stacking_relative_content_box = LogicalRect::from_physical(
             self.style.writing_mode,
@@ -3048,8 +3048,8 @@ impl ComputedValuesCursorUtility for ComputedValues {
     #[inline]
     fn get_cursor(&self, default_cursor: CursorKind) -> Option<CursorKind> {
         match (
-            self.get_inheritedui().pointer_events,
-            &self.get_inheritedui().cursor,
+            self.get_inherited_ui().pointer_events,
+            &self.get_inherited_ui().cursor,
         ) {
             (PointerEvents::None, _) => None,
             (
diff --git a/components/layout/flex.rs b/components/layout/flex.rs
index 42ed7910b8d..2864c922874 100644
--- a/components/layout/flex.rs
+++ b/components/layout/flex.rs
@@ -561,7 +561,7 @@ impl FlexFlow {
                                     .explicit_block_size(parent_container_size)
                                     .map(|x| max(x - box_border, Au(0)));
         let containing_block_text_align =
-            self.block_flow.fragment.style().get_inheritedtext().text_align;
+            self.block_flow.fragment.style().get_inherited_text().text_align;
 
         while let Some(mut line) = self.get_flex_line(inline_size) {
             let items = &mut self.items[line.range.clone()];
diff --git a/components/layout/fragment.rs b/components/layout/fragment.rs
index 38ea9d03b93..b7b3ac07d64 100644
--- a/components/layout/fragment.rs
+++ b/components/layout/fragment.rs
@@ -818,7 +818,7 @@ impl Fragment {
             SpecificFragmentInfo::TableCell => {
                 let base_quantities = QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_PADDING |
                     QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
-                if self.style.get_inheritedtable().border_collapse ==
+                if self.style.get_inherited_table().border_collapse ==
                         BorderCollapse::Separate {
                     base_quantities | QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
                 } else {
@@ -828,7 +828,7 @@ impl Fragment {
             SpecificFragmentInfo::TableWrapper => {
                 let base_quantities = QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_MARGINS |
                     QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
-                if self.style.get_inheritedtable().border_collapse ==
+                if self.style.get_inherited_table().border_collapse ==
                         BorderCollapse::Separate {
                     base_quantities | QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
                 } else {
@@ -838,7 +838,7 @@ impl Fragment {
             SpecificFragmentInfo::TableRow => {
                 let base_quantities =
                     QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
-                if self.style.get_inheritedtable().border_collapse ==
+                if self.style.get_inherited_table().border_collapse ==
                         BorderCollapse::Separate {
                     base_quantities | QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
                 } else {
@@ -1272,7 +1272,7 @@ impl Fragment {
     pub fn compute_border_and_padding(&mut self,
                                       containing_block_inline_size: Au) {
         // Compute border.
-        let border = match self.style.get_inheritedtable().border_collapse {
+        let border = match self.style.get_inherited_table().border_collapse {
             BorderCollapse::Separate => self.border_width(),
             BorderCollapse::Collapse => LogicalMargin::zero(self.style.writing_mode),
         };
@@ -1377,7 +1377,7 @@ impl Fragment {
     }
 
     pub fn white_space(&self) -> WhiteSpace {
-        self.style().get_inheritedtext().white_space
+        self.style().get_inherited_text().white_space
     }
 
     pub fn color(&self) -> Color {
@@ -1625,12 +1625,12 @@ impl Fragment {
         let mut flags = SplitOptions::empty();
         if starts_line {
             flags.insert(SplitOptions::STARTS_LINE);
-            if self.style().get_inheritedtext().overflow_wrap == OverflowWrap::BreakWord {
+            if self.style().get_inherited_text().overflow_wrap == OverflowWrap::BreakWord {
                 flags.insert(SplitOptions::RETRY_AT_CHARACTER_BOUNDARIES)
             }
         }
 
-        match self.style().get_inheritedtext().word_break {
+        match self.style().get_inherited_text().word_break {
             WordBreak::Normal | WordBreak::KeepAll => {
                 // Break at normal word boundaries. keep-all forbids soft wrap opportunities.
                 let natural_word_breaking_strategy =
diff --git a/components/layout/inline.rs b/components/layout/inline.rs
index 83961219e37..58d6a498457 100644
--- a/components/layout/inline.rs
+++ b/components/layout/inline.rs
@@ -934,7 +934,7 @@ impl InlineFlow {
         if fragments.fragments.is_empty() {
             return
         }
-        let text_justify = fragments.fragments[0].style().get_inheritedtext().text_justify;
+        let text_justify = fragments.fragments[0].style().get_inherited_text().text_justify;
 
         // Translate `left` and `right` to logical directions.
         let is_ltr = fragments.fragments[0].style().writing_mode.is_bidi_ltr();
@@ -1341,7 +1341,7 @@ impl Flow for InlineFlow {
         let mut intrinsic_sizes_for_nonbroken_run = IntrinsicISizesContribution::new();
         for fragment in &mut self.fragments.fragments {
             let intrinsic_sizes_for_fragment = fragment.compute_intrinsic_inline_sizes().finish();
-            match fragment.style.get_inheritedtext().white_space {
+            match fragment.style.get_inherited_text().white_space {
                 WhiteSpace::Nowrap => {
                     intrinsic_sizes_for_nonbroken_run.union_nonbreaking_inline(
                         &intrinsic_sizes_for_fragment)
diff --git a/components/layout/query.rs b/components/layout/query.rs
index b52d415939f..408e220dfe4 100644
--- a/components/layout/query.rs
+++ b/components/layout/query.rs
@@ -959,7 +959,7 @@ fn inner_text_collection_steps<N: LayoutNode>(node: N,
         };
 
         // Step 2.
-        if style.get_inheritedbox().visibility != Visibility::Visible {
+        if style.get_inherited_box().visibility != Visibility::Visible {
             continue;
         }
 
diff --git a/components/layout/table.rs b/components/layout/table.rs
index a258a570692..658a39d8e21 100644
--- a/components/layout/table.rs
+++ b/components/layout/table.rs
@@ -191,8 +191,8 @@ impl TableFlow {
     /// Returns the effective spacing per cell, taking the value of `border-collapse` into account.
     pub fn spacing(&self) -> border_spacing::T {
         let style = self.block_flow.fragment.style();
-        match style.get_inheritedtable().border_collapse {
-            border_collapse::T::Separate => style.get_inheritedtable().border_spacing,
+        match style.get_inherited_table().border_collapse {
+            border_collapse::T::Separate => style.get_inherited_table().border_spacing,
             border_collapse::T::Collapse => border_spacing::T::zero(),
         }
     }
@@ -298,7 +298,7 @@ impl Flow for TableFlow {
         let collapsing_borders = self.block_flow
                                      .fragment
                                      .style
-                                     .get_inheritedtable()
+                                     .get_inherited_table()
                                      .border_collapse == border_collapse::T::Collapse;
         let table_inline_collapsed_borders = if collapsing_borders {
             Some(TableInlineCollapsedBorders {
@@ -522,7 +522,7 @@ impl Flow for TableFlow {
         let border_painting_mode = match self.block_flow
                                              .fragment
                                              .style
-                                             .get_inheritedtable()
+                                             .get_inherited_table()
                                              .border_collapse {
             border_collapse::T::Separate => BorderPaintingMode::Separate,
             border_collapse::T::Collapse => BorderPaintingMode::Hidden,
@@ -771,12 +771,12 @@ pub trait TableLikeFlow {
 impl TableLikeFlow for BlockFlow {
     fn assign_block_size_for_table_like_flow(&mut self, block_direction_spacing: Au,
                                              layout_context: &LayoutContext) {
-        debug_assert!(self.fragment.style.get_inheritedtable().border_collapse ==
+        debug_assert!(self.fragment.style.get_inherited_table().border_collapse ==
                       border_collapse::T::Separate || block_direction_spacing == Au(0));
 
         fn border_spacing_for_row(fragment: &Fragment, row: &TableRowFlow,
                                   block_direction_spacing: Au) -> Au {
-            match fragment.style.get_inheritedtable().border_collapse {
+            match fragment.style.get_inherited_table().border_collapse {
                 border_collapse::T::Separate => block_direction_spacing,
                 border_collapse::T::Collapse => {
                     row.collapsed_border_spacing.block_start
@@ -1204,13 +1204,13 @@ impl<'table> TableCellStyleInfo<'table> {
         use style::computed_values::visibility::T as Visibility;
 
         if !self.cell.visible || self.cell.block_flow.fragment.style()
-                                     .get_inheritedbox().visibility != Visibility::Visible {
+                                     .get_inherited_box().visibility != Visibility::Visible {
             return
         }
         let border_painting_mode = match self.cell.block_flow
                                              .fragment
                                              .style
-                                             .get_inheritedtable()
+                                             .get_inherited_table()
                                              .border_collapse {
             border_collapse::T::Separate => BorderPaintingMode::Separate,
             border_collapse::T::Collapse => BorderPaintingMode::Collapse(&self.cell.collapsed_borders),
diff --git a/components/layout/table_row.rs b/components/layout/table_row.rs
index 933d3be632e..ffecce5d6c7 100644
--- a/components/layout/table_row.rs
+++ b/components/layout/table_row.rs
@@ -353,7 +353,7 @@ impl Flow for TableRowFlow {
         let collapsing_borders = self.block_flow
                                      .fragment
                                      .style()
-                                     .get_inheritedtable()
+                                     .get_inherited_table()
                                      .border_collapse == BorderCollapse::Collapse;
         let row_style = &*self.block_flow.fragment.style;
         self.preliminary_collapsed_borders.reset(
@@ -500,7 +500,7 @@ impl Flow for TableRowFlow {
 
         // Set up border collapse info.
         let border_collapse_info =
-            match self.block_flow.fragment.style().get_inheritedtable().border_collapse {
+            match self.block_flow.fragment.style().get_inherited_table().border_collapse {
                 BorderCollapse::Collapse => {
                     Some(BorderCollapseInfoForChildTableCell {
                         collapsed_borders_for_row: &self.final_collapsed_borders,
diff --git a/components/layout/table_rowgroup.rs b/components/layout/table_rowgroup.rs
index 85bccb18ade..cac1657bd43 100644
--- a/components/layout/table_rowgroup.rs
+++ b/components/layout/table_rowgroup.rs
@@ -130,7 +130,7 @@ impl Flow for TableRowGroupFlow {
         let (inline_start_content_edge, inline_end_content_edge) = (Au(0), Au(0));
         let content_inline_size = containing_block_inline_size;
 
-        let border_collapse = self.block_flow.fragment.style.get_inheritedtable().border_collapse;
+        let border_collapse = self.block_flow.fragment.style.get_inherited_table().border_collapse;
         let inline_size_computer = InternalTable;
         inline_size_computer.compute_used_inline_size(&mut self.block_flow,
                                                       shared_context,
diff --git a/components/layout/text.rs b/components/layout/text.rs
index 15fecd3f7d1..ac93eaed03f 100644
--- a/components/layout/text.rs
+++ b/components/layout/text.rs
@@ -170,7 +170,7 @@ impl TextRunScanner {
             {
                 let in_fragment = self.clump.front().unwrap();
                 let font_style = in_fragment.style().clone_font();
-                let inherited_text_style = in_fragment.style().get_inheritedtext();
+                let inherited_text_style = in_fragment.style().get_inherited_text();
                 font_group = font_context.font_group(font_style);
                 compression = match in_fragment.white_space() {
                     WhiteSpace::Normal |
@@ -477,7 +477,7 @@ pub fn font_metrics_for_style(mut font_context: &mut LayoutFontContext, style: :
 /// Returns the line block-size needed by the given computed style and font size.
 pub fn line_height_from_style(style: &ComputedValues, metrics: &FontMetrics) -> Au {
     let font_size = style.get_font().font_size.size();
-    match style.get_inheritedtext().line_height {
+    match style.get_inherited_text().line_height {
         LineHeight::Normal => Au::from(metrics.line_gap),
         LineHeight::Number(l) => font_size.scale_by(l.0),
         LineHeight::Length(l) => Au::from(l)
diff --git a/components/layout_thread/dom_wrapper.rs b/components/layout_thread/dom_wrapper.rs
index 309ddaf7e93..89a21ec64d5 100644
--- a/components/layout_thread/dom_wrapper.rs
+++ b/components/layout_thread/dom_wrapper.rs
@@ -979,7 +979,7 @@ impl<'ln> ThreadSafeLayoutNode for ServoThreadSafeLayoutNode<'ln> {
             //
             // If you implement other values for this property, you will almost certainly
             // want to update this check.
-            !self.style(context).get_inheritedtext().white_space.preserve_newlines()
+            !self.style(context).get_inherited_text().white_space.preserve_newlines()
         }
     }
 
diff --git a/components/layout_thread/lib.rs b/components/layout_thread/lib.rs
index f0383e871fa..3c39b95a28b 100644
--- a/components/layout_thread/lib.rs
+++ b/components/layout_thread/lib.rs
@@ -128,7 +128,7 @@ use style::context::{QuirksMode, RegisteredSpeculativePainter, RegisteredSpecula
 use style::context::{SharedStyleContext, StyleSystemOptions, ThreadLocalStyleContextCreationInfo};
 use style::dom::{ShowSubtree, ShowSubtreeDataAndPrimaryValues, TElement, TNode};
 use style::driver;
-use style::error_reporting::{NullReporter, RustLogReporter};
+use style::error_reporting::RustLogReporter;
 use style::invalidation::element::restyle_hints::RestyleHint;
 use style::logical_geometry::LogicalPoint;
 use style::media_queries::{Device, MediaList, MediaType};
@@ -1754,7 +1754,7 @@ fn get_ua_stylesheets() -> Result<UserAgentStylesheets, &'static str> {
             MediaList::empty(),
             shared_lock.clone(),
             None,
-            &NullReporter,
+            None,
             QuirksMode::NoQuirks,
         ))))
     }
@@ -1782,7 +1782,7 @@ fn get_ua_stylesheets() -> Result<UserAgentStylesheets, &'static str> {
                 MediaList::empty(),
                 shared_lock.clone(),
                 None,
-                &RustLogReporter,
+                Some(&RustLogReporter),
                 QuirksMode::NoQuirks,
             )))
         );
diff --git a/components/script/dom/css.rs b/components/script/dom/css.rs
index 4b67f516e83..d642b44a19f 100644
--- a/components/script/dom/css.rs
+++ b/components/script/dom/css.rs
@@ -42,7 +42,8 @@ impl CSS {
             &url,
             Some(CssRuleType::Style),
             ParsingMode::DEFAULT,
-            QuirksMode::NoQuirks
+            QuirksMode::NoQuirks,
+            None,
         );
         decl.eval(&context)
     }
@@ -58,7 +59,8 @@ impl CSS {
                 &url,
                 Some(CssRuleType::Style),
                 ParsingMode::DEFAULT,
-                QuirksMode::NoQuirks
+                QuirksMode::NoQuirks,
+                None,
             );
             cond.eval(&context)
         } else {
diff --git a/components/script/dom/cssmediarule.rs b/components/script/dom/cssmediarule.rs
index 0ecdf71a314..23f3c46a251 100644
--- a/components/script/dom/cssmediarule.rs
+++ b/components/script/dom/cssmediarule.rs
@@ -75,15 +75,15 @@ impl CSSMediaRule {
         let window = global.as_window();
         let url = window.get_url();
         let quirks_mode = window.Document().quirks_mode();
-        let context = ParserContext::new_for_cssom(&url, Some(CssRuleType::Media),
-                                                   ParsingMode::DEFAULT,
-                                                   quirks_mode);
-
-        let new_medialist = StyleMediaList::parse(
-            &context,
-            &mut input,
+        let context = ParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            quirks_mode,
             window.css_error_reporter(),
         );
+
+        let new_medialist = StyleMediaList::parse(&context, &mut input);
         let mut guard = self.cssconditionrule.shared_lock().write();
 
         // Clone an Arc because we can’t borrow `guard` twice at the same time.
diff --git a/components/script/dom/cssstyledeclaration.rs b/components/script/dom/cssstyledeclaration.rs
index e3a4a20d380..9f6c97dbc7d 100644
--- a/components/script/dom/cssstyledeclaration.rs
+++ b/components/script/dom/cssstyledeclaration.rs
@@ -181,6 +181,19 @@ macro_rules! css_properties(
     );
 );
 
+fn remove_property(
+    decls: &mut PropertyDeclarationBlock,
+    id: &PropertyId,
+) -> bool {
+    let first_declaration = decls.first_declaration_to_remove(id);
+    let first_declaration = match first_declaration {
+        Some(i) => i,
+        None => return false,
+    };
+    decls.remove_property(id, first_declaration);
+    true
+}
+
 impl CSSStyleDeclaration {
     #[allow(unrooted_must_root)]
     pub fn new_inherited(owner: CSSStyleOwner,
@@ -253,7 +266,7 @@ impl CSSStyleDeclaration {
         self.owner.mutate_associated_block(|pdb, changed| {
             if value.is_empty() {
                 // Step 3
-                *changed = pdb.remove_property(&id, |_| {});
+                *changed = remove_property(pdb, &id);
                 return Ok(());
             }
 
@@ -365,7 +378,7 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
         let mut string = String::new();
         self.owner.mutate_associated_block(|pdb, changed| {
             pdb.property_value_to_css(&id, &mut string).unwrap();
-            *changed = pdb.remove_property(&id, |_| {});
+            *changed = remove_property(pdb, &id);
         });
 
         // Step 6
diff --git a/components/script/dom/csssupportsrule.rs b/components/script/dom/csssupportsrule.rs
index 68d02aa241a..a96cd706b86 100644
--- a/components/script/dom/csssupportsrule.rs
+++ b/components/script/dom/csssupportsrule.rs
@@ -63,9 +63,13 @@ impl CSSSupportsRule {
             let win = global.as_window();
             let url = win.Document().url();
             let quirks_mode = win.Document().quirks_mode();
-            let context = ParserContext::new_for_cssom(&url, Some(CssRuleType::Supports),
-                                                       ParsingMode::DEFAULT,
-                                                       quirks_mode);
+            let context = ParserContext::new_for_cssom(
+                &url,
+                Some(CssRuleType::Supports),
+                ParsingMode::DEFAULT,
+                quirks_mode,
+                None,
+            );
             let enabled = cond.eval(&context);
             let mut guard = self.cssconditionrule.shared_lock().write();
             let rule = self.supportsrule.write_with(&mut guard);
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 9e048161633..26c59bdb8ec 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -127,6 +127,7 @@ use std::cell::{Cell, Ref, RefMut};
 use std::collections::{HashMap, HashSet, VecDeque};
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::default::Default;
+use std::fmt;
 use std::mem;
 use std::ptr::NonNull;
 use std::rc::Rc;
@@ -213,6 +214,12 @@ struct StyleSheetInDocument {
     owner: Dom<Element>,
 }
 
+impl fmt::Debug for StyleSheetInDocument {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        self.sheet.fmt(formatter)
+    }
+}
+
 impl PartialEq for StyleSheetInDocument {
     fn eq(&self, other: &Self) -> bool {
         Arc::ptr_eq(&self.sheet, &other.sheet)
diff --git a/components/script/dom/htmlimageelement.rs b/components/script/dom/htmlimageelement.rs
index 8206af23e3e..61acecda71d 100644
--- a/components/script/dom/htmlimageelement.rs
+++ b/components/script/dom/htmlimageelement.rs
@@ -770,10 +770,13 @@ pub fn parse_a_sizes_attribute(input: DOMString, width: Option<u32>) -> Vec<Size
         }
         let mut input = ParserInput::new(&trimmed);
         let url = ServoUrl::parse("about:blank").unwrap();
-        let context = ParserContext::new_for_cssom(&url,
-                                                   None,
-                                                   ParsingMode::empty(),
-                                                   QuirksMode::NoQuirks);
+        let context = ParserContext::new_for_cssom(
+            &url,
+            None,
+            ParsingMode::empty(),
+            QuirksMode::NoQuirks,
+            None,
+        );
         let mut parser = Parser::new(&mut input);
         let length = parser.try(|i| Length::parse_non_negative(&context, i));
         match length {
diff --git a/components/script/dom/htmllinkelement.rs b/components/script/dom/htmllinkelement.rs
index ab84906d223..a86789dcd71 100644
--- a/components/script/dom/htmllinkelement.rs
+++ b/components/script/dom/htmllinkelement.rs
@@ -277,6 +277,7 @@ impl HTMLLinkElement {
         let mut input = ParserInput::new(&mq_str);
         let mut css_parser = CssParser::new(&mut input);
         let doc_url = document.url();
+        let window = document.window();
         // FIXME(emilio): This looks somewhat fishy, since we use the context
         // only to parse the media query list, CssRuleType::Media doesn't make
         // much sense.
@@ -285,13 +286,9 @@ impl HTMLLinkElement {
             Some(CssRuleType::Media),
             ParsingMode::DEFAULT,
             document.quirks_mode(),
-        );
-        let window = document.window();
-        let media = MediaList::parse(
-            &context,
-            &mut css_parser,
             window.css_error_reporter(),
         );
+        let media = MediaList::parse(&context, &mut css_parser);
 
         let im_attribute = element.get_attribute(&ns!(), &local_name!("integrity"));
         let integrity_val = im_attribute.r().map(|a| a.value());
diff --git a/components/script/dom/htmlstyleelement.rs b/components/script/dom/htmlstyleelement.rs
index 6778af92218..82da9ba6180 100644
--- a/components/script/dom/htmlstyleelement.rs
+++ b/components/script/dom/htmlstyleelement.rs
@@ -84,25 +84,32 @@ impl HTMLStyleElement {
 
         let data = node.GetTextContent().expect("Element.textContent must be a string");
         let url = window.get_url();
-        let context = CssParserContext::new_for_cssom(&url,
-                                                      Some(CssRuleType::Media),
-                                                      ParsingMode::DEFAULT,
-                                                      doc.quirks_mode());
+        let css_error_reporter = window.css_error_reporter();
+        let context = CssParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            doc.quirks_mode(),
+            css_error_reporter,
+        );
         let shared_lock = node.owner_doc().style_shared_lock().clone();
         let mut input = ParserInput::new(&mq_str);
-        let css_error_reporter = window.css_error_reporter();
         let mq = Arc::new(shared_lock.wrap(MediaList::parse(
             &context,
             &mut CssParser::new(&mut input),
-            css_error_reporter),
-        ));
+        )));
         let loader = StylesheetLoader::for_element(self.upcast());
-        let sheet = Stylesheet::from_str(&data, window.get_url(),
-                                         Origin::Author, mq,
-                                         shared_lock, Some(&loader),
-                                         css_error_reporter,
-                                         doc.quirks_mode(),
-                                         self.line_number as u32);
+        let sheet = Stylesheet::from_str(
+            &data,
+            window.get_url(),
+            Origin::Author,
+            mq,
+            shared_lock,
+            Some(&loader),
+            css_error_reporter,
+            doc.quirks_mode(),
+            self.line_number as u32,
+        );
 
         let sheet = Arc::new(sheet);
 
diff --git a/components/script/dom/medialist.rs b/components/script/dom/medialist.rs
index 2f5b33c1016..d43f6d3a710 100644
--- a/components/script/dom/medialist.rs
+++ b/components/script/dom/medialist.rs
@@ -77,14 +77,14 @@ impl MediaListMethods for MediaList {
         let window = global.as_window();
         let url = window.get_url();
         let quirks_mode = window.Document().quirks_mode();
-        let context = ParserContext::new_for_cssom(&url, Some(CssRuleType::Media),
-                                                   ParsingMode::DEFAULT,
-                                                   quirks_mode);
-        *media_queries = StyleMediaList::parse(
-            &context,
-            &mut parser,
+        let context = ParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            quirks_mode,
             window.css_error_reporter(),
         );
+        *media_queries = StyleMediaList::parse(&context, &mut parser);
     }
 
     // https://drafts.csswg.org/cssom/#dom-medialist-length
@@ -117,9 +117,13 @@ impl MediaListMethods for MediaList {
         let win = global.as_window();
         let url = win.get_url();
         let quirks_mode = win.Document().quirks_mode();
-        let context = ParserContext::new_for_cssom(&url, Some(CssRuleType::Media),
-                                                   ParsingMode::DEFAULT,
-                                                   quirks_mode);
+        let context = ParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            quirks_mode,
+            win.css_error_reporter(),
+        );
         let m = MediaQuery::parse(&context, &mut parser);
         // Step 2
         if let Err(_) = m {
@@ -146,9 +150,13 @@ impl MediaListMethods for MediaList {
         let win = global.as_window();
         let url = win.get_url();
         let quirks_mode = win.Document().quirks_mode();
-        let context = ParserContext::new_for_cssom(&url, Some(CssRuleType::Media),
-                                                   ParsingMode::DEFAULT,
-                                                   quirks_mode);
+        let context = ParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            quirks_mode,
+            win.css_error_reporter(),
+        );
         let m = MediaQuery::parse(&context, &mut parser);
         // Step 2
         if let Err(_) = m {
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 0f259dd2ea7..b536f28345f 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -100,6 +100,7 @@ use std::sync::{Arc, Mutex};
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::{Sender, channel};
 use std::sync::mpsc::TryRecvError::{Disconnected, Empty};
+use style::error_reporting::ParseErrorReporter;
 use style::media_queries;
 use style::parser::ParserContext as CssParserContext;
 use style::properties::{ComputedValues, PropertyId};
@@ -389,8 +390,8 @@ impl Window {
          &self.bluetooth_extra_permission_data
     }
 
-    pub fn css_error_reporter(&self) -> &CSSErrorReporter {
-        &self.error_reporter
+    pub fn css_error_reporter(&self) -> Option<&ParseErrorReporter> {
+        Some(&self.error_reporter)
     }
 
     /// Sets a new list of scroll offsets.
@@ -1017,14 +1018,15 @@ impl WindowMethods for Window {
         let mut parser = Parser::new(&mut input);
         let url = self.get_url();
         let quirks_mode = self.Document().quirks_mode();
-        let context = CssParserContext::new_for_cssom(&url, Some(CssRuleType::Media),
-                                                      ParsingMode::DEFAULT,
-                                                      quirks_mode);
-        let media_query_list = media_queries::MediaList::parse(
-            &context,
-            &mut parser,
+        let context = CssParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            quirks_mode,
             self.css_error_reporter(),
         );
+        let media_query_list =
+            media_queries::MediaList::parse(&context, &mut parser);
         let document = self.Document();
         let mql = MediaQueryList::new(&document, media_query_list);
         self.media_query_lists.push(&*mql);
diff --git a/components/style/counter_style/mod.rs b/components/style/counter_style/mod.rs
index 94b10aa0d33..2542dee3625 100644
--- a/components/style/counter_style/mod.rs
+++ b/components/style/counter_style/mod.rs
@@ -9,8 +9,8 @@
 use Atom;
 use cssparser::{AtRuleParser, DeclarationListParser, DeclarationParser};
 use cssparser::{CowRcStr, Parser, SourceLocation, Token};
-use error_reporting::{ContextualParseError, ParseErrorReporter};
-use parser::{Parse, ParserContext, ParserErrorContext};
+use error_reporting::ContextualParseError;
+use parser::{Parse, ParserContext};
 use selectors::parser::SelectorParseErrorKind;
 use shared_lock::{SharedRwLockReadGuard, ToCssWithGuard};
 use std::fmt::{self, Write};
@@ -73,16 +73,12 @@ pub fn parse_counter_style_name_definition<'i, 't>(
 }
 
 /// Parse the body (inside `{}`) of an @counter-style rule
-pub fn parse_counter_style_body<'i, 't, R>(
+pub fn parse_counter_style_body<'i, 't>(
     name: CustomIdent,
     context: &ParserContext,
-    error_context: &ParserErrorContext<R>,
     input: &mut Parser<'i, 't>,
     location: SourceLocation,
-) -> Result<CounterStyleRuleData, ParseError<'i>>
-where
-    R: ParseErrorReporter,
-{
+) -> Result<CounterStyleRuleData, ParseError<'i>> {
     let start = input.current_source_location();
     let mut rule = CounterStyleRuleData::empty(name, location);
     {
@@ -98,7 +94,7 @@ where
                     slice,
                     error,
                 );
-                context.log_css_error(error_context, location, error)
+                context.log_css_error(location, error)
             }
         }
     }
@@ -134,7 +130,7 @@ where
         _ => None,
     };
     if let Some(error) = error {
-        context.log_css_error(error_context, start, error);
+        context.log_css_error(start, error);
         Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
     } else {
         Ok(rule)
diff --git a/components/style/encoding_support.rs b/components/style/encoding_support.rs
index eadcfa4c159..7aec18bee2c 100644
--- a/components/style/encoding_support.rs
+++ b/components/style/encoding_support.rs
@@ -55,7 +55,7 @@ impl Stylesheet {
     ///
     /// Takes care of decoding the network bytes and forwards the resulting
     /// string to `Stylesheet::from_str`.
-    pub fn from_bytes<R>(
+    pub fn from_bytes(
         bytes: &[u8],
         url_data: UrlExtraData,
         protocol_encoding_label: Option<&str>,
@@ -64,12 +64,9 @@ impl Stylesheet {
         media: MediaList,
         shared_lock: SharedRwLock,
         stylesheet_loader: Option<&StylesheetLoader>,
-        error_reporter: &R,
+        error_reporter: Option<&ParseErrorReporter>,
         quirks_mode: QuirksMode,
-    ) -> Stylesheet
-    where
-        R: ParseErrorReporter,
-    {
+    ) -> Stylesheet {
         let string = decode_stylesheet_bytes(bytes, protocol_encoding_label, environment_encoding);
         Stylesheet::from_str(
             &string,
@@ -86,17 +83,15 @@ impl Stylesheet {
 
     /// Updates an empty stylesheet with a set of bytes that reached over the
     /// network.
-    pub fn update_from_bytes<R>(
+    pub fn update_from_bytes(
         existing: &Stylesheet,
         bytes: &[u8],
         protocol_encoding_label: Option<&str>,
         environment_encoding: Option<&'static encoding_rs::Encoding>,
         url_data: UrlExtraData,
         stylesheet_loader: Option<&StylesheetLoader>,
-        error_reporter: &R,
-    ) where
-        R: ParseErrorReporter,
-    {
+        error_reporter: Option<&ParseErrorReporter>,
+    ) {
         let string = decode_stylesheet_bytes(bytes, protocol_encoding_label, environment_encoding);
         Self::update_from_str(
             existing,
diff --git a/components/style/error_reporting.rs b/components/style/error_reporting.rs
index 2af76be87b9..b5d5ba17ef8 100644
--- a/components/style/error_reporting.rs
+++ b/components/style/error_reporting.rs
@@ -7,7 +7,6 @@
 #![deny(missing_docs)]
 
 use cssparser::{BasicParseErrorKind, ParseErrorKind, SourceLocation, Token};
-use log;
 use std::fmt;
 use style_traits::ParseError;
 use stylesheets::UrlExtraData;
@@ -229,8 +228,10 @@ pub trait ParseErrorReporter {
 /// This logging is silent by default, and can be enabled with a `RUST_LOG=style=info`
 /// environment variable.
 /// (See [`env_logger`](https://rust-lang-nursery.github.io/log/env_logger/).)
+#[cfg(feature = "servo")]
 pub struct RustLogReporter;
 
+#[cfg(feature = "servo")]
 impl ParseErrorReporter for RustLogReporter {
     fn report_error(
         &self,
@@ -238,6 +239,7 @@ impl ParseErrorReporter for RustLogReporter {
         location: SourceLocation,
         error: ContextualParseError,
     ) {
+        use log;
         if log_enabled!(log::Level::Info) {
             info!(
                 "Url:\t{}\n{}:{} {}",
@@ -249,17 +251,3 @@ impl ParseErrorReporter for RustLogReporter {
         }
     }
 }
-
-/// Error reporter which silently forgets errors
-pub struct NullReporter;
-
-impl ParseErrorReporter for NullReporter {
-    fn report_error(
-        &self,
-        _url: &UrlExtraData,
-        _location: SourceLocation,
-        _error: ContextualParseError,
-    ) {
-        // do nothing
-    }
-}
diff --git a/components/style/font_face.rs b/components/style/font_face.rs
index 57c0f3b0b77..d7501c1cca7 100644
--- a/components/style/font_face.rs
+++ b/components/style/font_face.rs
@@ -10,8 +10,8 @@ use cssparser::{AtRuleParser, DeclarationListParser, DeclarationParser, Parser};
 use cssparser::{CowRcStr, SourceLocation};
 #[cfg(feature = "gecko")]
 use cssparser::UnicodeRange;
-use error_reporting::{ContextualParseError, ParseErrorReporter};
-use parser::{Parse, ParserContext, ParserErrorContext};
+use error_reporting::ContextualParseError;
+use parser::{Parse, ParserContext};
 #[cfg(feature = "gecko")]
 use properties::longhands::font_language_override;
 use selectors::parser::SelectorParseErrorKind;
@@ -186,15 +186,11 @@ impl ToCss for FontStyle {
 /// Parse the block inside a `@font-face` rule.
 ///
 /// Note that the prelude parsing code lives in the `stylesheets` module.
-pub fn parse_font_face_block<R>(
+pub fn parse_font_face_block(
     context: &ParserContext,
-    error_context: &ParserErrorContext<R>,
     input: &mut Parser,
     location: SourceLocation,
-) -> FontFaceRuleData
-where
-    R: ParseErrorReporter,
-{
+) -> FontFaceRuleData {
     let mut rule = FontFaceRuleData::empty(location);
     {
         let parser = FontFaceRuleParser {
@@ -206,7 +202,7 @@ where
             if let Err((error, slice)) = declaration {
                 let location = error.location;
                 let error = ContextualParseError::UnsupportedFontFaceDescriptor(slice, error);
-                context.log_css_error(error_context, location, error)
+                context.log_css_error(location, error)
             }
         }
     }
diff --git a/components/style/gecko/data.rs b/components/style/gecko/data.rs
index a4ed8294ac2..6b9005c7560 100644
--- a/components/style/gecko/data.rs
+++ b/components/style/gecko/data.rs
@@ -18,13 +18,24 @@ use properties::ComputedValues;
 use selector_parser::SnapshotMap;
 use servo_arc::Arc;
 use shared_lock::{Locked, SharedRwLockReadGuard, StylesheetGuards};
+use std::fmt;
 use stylesheets::{CssRule, Origin, StylesheetContents, StylesheetInDocument};
 use stylist::Stylist;
 
 /// Little wrapper to a Gecko style sheet.
-#[derive(Debug, Eq, PartialEq)]
+#[derive(Eq, PartialEq)]
 pub struct GeckoStyleSheet(*const DomStyleSheet);
 
+impl fmt::Debug for GeckoStyleSheet {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        let contents = self.contents();
+        formatter.debug_struct("GeckoStyleSheet")
+            .field("origin", &contents.origin)
+            .field("url_data", &*contents.url_data.read())
+            .finish()
+    }
+}
+
 impl ToMediaListKey for ::gecko::data::GeckoStyleSheet {
     fn to_media_list_key(&self) -> MediaListKey {
         use std::mem;
diff --git a/components/style/gecko/media_queries.rs b/components/style/gecko/media_queries.rs
index 1c34762f286..771f4570b47 100644
--- a/components/style/gecko/media_queries.rs
+++ b/components/style/gecko/media_queries.rs
@@ -64,6 +64,27 @@ pub struct Device {
     used_viewport_size: AtomicBool,
 }
 
+impl fmt::Debug for Device {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use nsstring::nsCString;
+
+        let mut doc_uri = nsCString::new();
+        unsafe {
+            let doc =
+                &*self.pres_context().mDocument.raw::<structs::nsIDocument>();
+
+            bindings::Gecko_nsIURI_Debug(
+                doc.mDocumentURI.raw::<structs::nsIURI>(),
+                &mut doc_uri,
+            )
+        };
+
+        f.debug_struct("Device")
+            .field("document_url", &doc_uri)
+            .finish()
+    }
+}
+
 unsafe impl Sync for Device {}
 unsafe impl Send for Device {}
 
diff --git a/components/style/gecko/url.rs b/components/style/gecko/url.rs
index cb503f4720a..b94d2139764 100644
--- a/components/style/gecko/url.rs
+++ b/components/style/gecko/url.rs
@@ -6,7 +6,7 @@
 
 use cssparser::Parser;
 use gecko_bindings::bindings;
-use gecko_bindings::structs::{ServoBundledURI, URLExtraData};
+use gecko_bindings::structs::ServoBundledURI;
 use gecko_bindings::structs::mozilla::css::URLValueData;
 use gecko_bindings::structs::root::{RustString, nsStyleImageRequest};
 use gecko_bindings::structs::root::mozilla::css::{ImageValue, URLValue};
@@ -18,6 +18,7 @@ use servo_arc::{Arc, RawOffsetArc};
 use std::fmt::{self, Write};
 use std::mem;
 use style_traits::{CssWriter, ParseError, ToCss};
+use stylesheets::UrlExtraData;
 use values::computed::{Context, ToComputedValue};
 
 /// A CSS url() value for gecko.
@@ -32,7 +33,7 @@ pub struct CssUrl {
 
     /// The URL extra data.
     #[css(skip)]
-    pub extra_data: RefPtr<URLExtraData>,
+    pub extra_data: UrlExtraData,
 }
 
 impl CssUrl {
@@ -58,7 +59,7 @@ impl CssUrl {
             &url.mString as *const _ as *const RawOffsetArc<String>;
         CssUrl {
             serialization: Arc::from_raw_offset((*arc_type).clone()),
-            extra_data: url.mExtraData.to_safe(),
+            extra_data: UrlExtraData(url.mExtraData.to_safe()),
         }
     }
 
@@ -88,7 +89,7 @@ impl CssUrl {
         let arc_offset = Arc::into_raw_offset(self.serialization.clone());
         ServoBundledURI {
             mURLString: unsafe { mem::transmute::<_, RawOffsetArc<RustString>>(arc_offset) },
-            mExtraData: self.extra_data.get(),
+            mExtraData: self.extra_data.0.get(),
         }
     }
 }
diff --git a/components/style/gecko_bindings/sugar/refptr.rs b/components/style/gecko_bindings/sugar/refptr.rs
index 10c9e627699..6a32b81430e 100644
--- a/components/style/gecko_bindings/sugar/refptr.rs
+++ b/components/style/gecko_bindings/sugar/refptr.rs
@@ -78,15 +78,6 @@ impl<T: RefCounted> RefPtr<T> {
         ret
     }
 
-    /// Create a reference to RefPtr from a reference to pointer.
-    ///
-    /// The pointer must be valid and non null.
-    ///
-    /// This method doesn't touch refcount.
-    pub unsafe fn from_ptr_ref(ptr: &*mut T) -> &Self {
-        mem::transmute(ptr)
-    }
-
     /// Produces an FFI-compatible RefPtr that can be stored in style structs.
     ///
     /// structs::RefPtr does not have a destructor, so this may leak
diff --git a/components/style/gecko_string_cache/mod.rs b/components/style/gecko_string_cache/mod.rs
index 297599e2080..b0c8750265b 100644
--- a/components/style/gecko_string_cache/mod.rs
+++ b/components/style/gecko_string_cache/mod.rs
@@ -122,7 +122,8 @@ impl WeakAtom {
             unsafe { u8_ptr.offset(string_offset) as *const u16 }
         } else {
             let atom_ptr = self.as_ptr() as *const nsDynamicAtom;
-            unsafe { (*(atom_ptr)).mString }
+            // Dynamic atom chars are stored at the end of the object.
+            unsafe { atom_ptr.offset(1) as *const u16 }
         };
         unsafe { slice::from_raw_parts(string, self.len() as usize) }
     }
diff --git a/components/style/media_queries/media_list.rs b/components/style/media_queries/media_list.rs
index 5243174e07f..a5604b6dc19 100644
--- a/components/style/media_queries/media_list.rs
+++ b/components/style/media_queries/media_list.rs
@@ -9,13 +9,13 @@
 use context::QuirksMode;
 use cssparser::{Delimiter, Parser};
 use cssparser::{ParserInput, Token};
-use error_reporting::{ContextualParseError, ParseErrorReporter};
-use parser::{ParserContext, ParserErrorContext};
+use error_reporting::ContextualParseError;
+use parser::ParserContext;
 use super::{Device, MediaQuery, Qualifier};
 
 /// A type that encapsulates a media query list.
-#[css(comma)]
-#[derive(Clone, Debug, MallocSizeOf, ToCss)]
+#[css(comma, derive_debug)]
+#[derive(Clone, MallocSizeOf, ToCss)]
 pub struct MediaList {
     /// The list of media queries.
     #[css(iterable)]
@@ -30,14 +30,10 @@ impl MediaList {
     /// "not all", see:
     ///
     /// <https://drafts.csswg.org/mediaqueries/#error-handling>
-    pub fn parse<R>(
+    pub fn parse(
         context: &ParserContext,
         input: &mut Parser,
-        error_reporter: &R,
-    ) -> MediaList
-    where
-        R: ParseErrorReporter,
-    {
+    ) -> Self {
         if input.is_exhausted() {
             return Self::empty();
         }
@@ -54,8 +50,7 @@ impl MediaList {
                     let location = err.location;
                     let error =
                         ContextualParseError::InvalidMediaRule(input.slice_from(start_position), err);
-                    let error_context = ParserErrorContext { error_reporter };
-                    context.log_css_error(&error_context, location, error);
+                    context.log_css_error(location, error);
                 },
             }
 
diff --git a/components/style/parser.rs b/components/style/parser.rs
index 6dbfe1cfa01..a4b7d816203 100644
--- a/components/style/parser.rs
+++ b/components/style/parser.rs
@@ -36,12 +36,6 @@ pub fn assert_parsing_mode_match() {
     }
 }
 
-/// The context required to report a parse error.
-pub struct ParserErrorContext<'a, R: 'a> {
-    /// An error reporter to report syntax errors.
-    pub error_reporter: &'a R,
-}
-
 /// The data that the parser needs from outside in order to parse a stylesheet.
 pub struct ParserContext<'a> {
     /// The `Origin` of the stylesheet, whether it's a user, author or
@@ -55,6 +49,8 @@ pub struct ParserContext<'a> {
     pub parsing_mode: ParsingMode,
     /// The quirks mode of this stylesheet.
     pub quirks_mode: QuirksMode,
+    /// The active error reporter, or none if error reporting is disabled.
+    error_reporter: Option<&'a ParseErrorReporter>,
     /// The currently active namespaces.
     pub namespaces: Option<&'a Namespaces>,
 }
@@ -68,6 +64,7 @@ impl<'a> ParserContext<'a> {
         rule_type: Option<CssRuleType>,
         parsing_mode: ParsingMode,
         quirks_mode: QuirksMode,
+        error_reporter: Option<&'a ParseErrorReporter>,
     ) -> Self {
         ParserContext {
             stylesheet_origin,
@@ -75,6 +72,7 @@ impl<'a> ParserContext<'a> {
             rule_type,
             parsing_mode,
             quirks_mode,
+            error_reporter,
             namespaces: None,
         }
     }
@@ -86,6 +84,7 @@ impl<'a> ParserContext<'a> {
         rule_type: Option<CssRuleType>,
         parsing_mode: ParsingMode,
         quirks_mode: QuirksMode,
+        error_reporter: Option<&'a ParseErrorReporter>,
     ) -> Self {
         Self::new(
             Origin::Author,
@@ -93,6 +92,7 @@ impl<'a> ParserContext<'a> {
             rule_type,
             parsing_mode,
             quirks_mode,
+            error_reporter,
         )
     }
 
@@ -110,6 +110,7 @@ impl<'a> ParserContext<'a> {
             parsing_mode: context.parsing_mode,
             quirks_mode: context.quirks_mode,
             namespaces: Some(namespaces),
+            error_reporter: context.error_reporter,
         }
     }
 
@@ -127,21 +128,17 @@ impl<'a> ParserContext<'a> {
     }
 
     /// Record a CSS parse error with this context’s error reporting.
-    pub fn log_css_error<R>(
+    pub fn log_css_error(
         &self,
-        context: &ParserErrorContext<R>,
         location: SourceLocation,
         error: ContextualParseError,
-    ) where
-        R: ParseErrorReporter,
-    {
-        let location = SourceLocation {
-            line: location.line,
-            column: location.column,
+    ) {
+        let error_reporter = match self.error_reporter {
+            Some(r) => r,
+            None => return,
         };
-        context
-            .error_reporter
-            .report_error(self.url_data, location, error)
+
+        error_reporter.report_error(self.url_data, location, error)
     }
 
     /// Returns whether chrome-only rules should be parsed.
diff --git a/components/style/properties/build.py b/components/style/properties/build.py
index 04418723ee4..4f5da29246b 100644
--- a/components/style/properties/build.py
+++ b/components/style/properties/build.py
@@ -19,6 +19,34 @@ import data
 
 RE_PYTHON_ADDR = re.compile(r'<.+? object at 0x[0-9a-fA-F]+>')
 
+OUT_DIR = os.environ.get("OUT_DIR", "")
+
+STYLE_STRUCT_LIST = [
+    "background",
+    "border",
+    "box",
+    "color",
+    "column",
+    "counters",
+    "effects",
+    "font",
+    "inherited_box",
+    "inherited_table",
+    "inherited_text",
+    "inherited_ui",
+    "inherited_svg",
+    "list",
+    "margin",
+    "outline",
+    "padding",
+    "position",
+    "table",
+    "text",
+    "ui",
+    "svg",
+    "xul",
+]
+
 
 def main():
     usage = "Usage: %s [ servo | gecko ] [ style-crate | geckolib <template> | html ]" % sys.argv[0]
@@ -31,14 +59,41 @@ def main():
         abort(usage)
 
     properties = data.PropertiesData(product=product)
-    template = os.path.join(BASE, "properties.mako.rs")
-    rust = render(template, product=product, data=properties, __file__=template)
+    files = {}
+    for kind in ["longhands", "shorthands"]:
+        files[kind] = {}
+        for struct in STYLE_STRUCT_LIST:
+            file_name = os.path.join(BASE, kind, "{}.mako.rs".format(struct))
+            if kind == "shorthands" and not os.path.exists(file_name):
+                files[kind][struct] = ""
+                continue
+            files[kind][struct] = render(
+                file_name,
+                product=product,
+                data=properties,
+            )
+    properties_template = os.path.join(BASE, "properties.mako.rs")
+    files["properties"] = render(
+        properties_template,
+        product=product,
+        data=properties,
+        __file__=properties_template,
+        OUT_DIR=OUT_DIR,
+    )
     if output == "style-crate":
-        write(os.environ["OUT_DIR"], "properties.rs", rust)
+        write(OUT_DIR, "properties.rs", files["properties"])
+        for kind in ["longhands", "shorthands"]:
+            for struct in files[kind]:
+                write(
+                    os.path.join(OUT_DIR, kind),
+                    "{}.rs".format(struct),
+                    files[kind][struct],
+                )
+
         if product == "gecko":
             template = os.path.join(BASE, "gecko.mako.rs")
             rust = render(template, data=properties)
-            write(os.environ["OUT_DIR"], "gecko_properties.rs", rust)
+            write(OUT_DIR, "gecko_properties.rs", rust)
     elif output == "geckolib":
         if len(sys.argv) < 4:
             abort(usage)
diff --git a/components/style/properties/data.py b/components/style/properties/data.py
index fca4b536e01..08001628e60 100644
--- a/components/style/properties/data.py
+++ b/components/style/properties/data.py
@@ -38,6 +38,10 @@ def to_rust_ident(name):
     return name
 
 
+def to_snake_case(ident):
+    return re.sub("([A-Z]+)", lambda m: "_" + m.group(1).lower(), ident).strip("_")
+
+
 def to_camel_case(ident):
     return re.sub("(^|_|-)([a-z0-9])", lambda m: m.group(2).upper(), ident.strip("_").strip("-"))
 
@@ -451,7 +455,7 @@ class StyleStruct(object):
     def __init__(self, name, inherited, gecko_name=None, additional_methods=None):
         self.gecko_struct_name = "Gecko" + name
         self.name = name
-        self.name_lower = name.lower()
+        self.name_lower = to_snake_case(name)
         self.ident = to_rust_ident(self.name_lower)
         self.longhands = []
         self.inherited = inherited
diff --git a/components/style/properties/declaration_block.rs b/components/style/properties/declaration_block.rs
index 4e368c0c2b7..8727ba4cc41 100644
--- a/components/style/properties/declaration_block.rs
+++ b/components/style/properties/declaration_block.rs
@@ -11,8 +11,8 @@ use cssparser::{DeclarationListParser, parse_important, ParserInput, CowRcStr};
 use cssparser::{Parser, AtRuleParser, DeclarationParser, Delimiter, ParseErrorKind};
 use custom_properties::CustomPropertiesBuilder;
 use error_reporting::{ParseErrorReporter, ContextualParseError};
-use parser::{ParserContext, ParserErrorContext};
-use properties::animated_properties::AnimationValue;
+use parser::ParserContext;
+use properties::animated_properties::{AnimationValue, AnimationValueMap};
 use shared_lock::Locked;
 use smallbitvec::{self, SmallBitVec};
 use smallvec::SmallVec;
@@ -24,7 +24,6 @@ use style_traits::{CssWriter, ParseError, ParsingMode, StyleParseErrorKind, ToCs
 use stylesheets::{CssRuleType, Origin, UrlExtraData};
 use super::*;
 use values::computed::Context;
-#[cfg(feature = "gecko")] use properties::animated_properties::AnimationValueMap;
 
 /// The animation rules.
 ///
@@ -564,51 +563,71 @@ impl PropertyDeclarationBlock {
         true
     }
 
-    /// <https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-removeproperty>
-    ///
-    /// Returns whether any declaration was actually removed.
-    pub fn remove_property<C>(
-        &mut self,
+    /// Returns the first declaration that would be removed by removing
+    /// `property`.
+    #[inline]
+    pub fn first_declaration_to_remove(
+        &self,
         property: &PropertyId,
-        mut before_change_callback: C,
-    ) -> bool
-    where
-        C: FnMut(&Self),
-    {
-        let longhand_id = property.longhand_id();
-        if let Some(id) = longhand_id {
+    ) -> Option<usize> {
+        if let Some(id) = property.longhand_id() {
             if !self.longhands.contains(id) {
-                return false
+                return None;
             }
         }
-        let mut removed_at_least_one = false;
-        let mut i = 0;
-        let mut len = self.len();
-        while i < len {
-            {
-                let id = self.declarations[i].id();
-                if !id.is_or_is_longhand_of(property) {
-                    i += 1;
-                    continue;
-                }
 
-                if !removed_at_least_one {
-                    before_change_callback(&*self);
-                }
-                removed_at_least_one = true;
-                if let PropertyDeclarationId::Longhand(id) = id {
-                    self.longhands.remove(id);
-                }
-                self.declarations_importance.remove(i);
+        self.declarations.iter().position(|declaration| {
+            declaration.id().is_or_is_longhand_of(property)
+        })
+    }
+
+    /// Removes a given declaration at a given index.
+    #[inline]
+    fn remove_declaration_at(&mut self, i: usize) {
+        {
+            let id = self.declarations[i].id();
+            if let PropertyDeclarationId::Longhand(id) = id {
+                self.longhands.remove(id);
             }
-            self.declarations.remove(i);
-            len -= 1;
+            self.declarations_importance.remove(i);
         }
+        self.declarations.remove(i);
+    }
 
-        if longhand_id.is_some() {
-            debug_assert!(removed_at_least_one);
+    /// <https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-removeproperty>
+    ///
+    /// `first_declaration` needs to be the result of
+    /// `first_declaration_to_remove`.
+    #[inline]
+    pub fn remove_property(
+        &mut self,
+        property: &PropertyId,
+        first_declaration: usize,
+    ) {
+        debug_assert_eq!(
+            Some(first_declaration),
+            self.first_declaration_to_remove(property)
+        );
+        debug_assert!(self.declarations[first_declaration].id().is_or_is_longhand_of(property));
+
+        self.remove_declaration_at(first_declaration);
+
+        let shorthand = match property.as_shorthand() {
+            Ok(s) => s,
+            Err(_longhand_or_custom) => return,
+        };
+
+        let mut i = first_declaration;
+        let mut len = self.len();
+        while i < len {
+            if !self.declarations[i].id().is_longhand_of(shorthand) {
+                i += 1;
+                continue;
+            }
+
+            self.remove_declaration_at(i);
+            len -= 1;
         }
-        removed_at_least_one
     }
 
     /// Take a declaration block known to contain a single property and serialize it.
@@ -667,7 +686,6 @@ impl PropertyDeclarationBlock {
     }
 
     /// Convert AnimationValueMap to PropertyDeclarationBlock.
-    #[cfg(feature = "gecko")]
     pub fn from_animation_value_map(animation_value_map: &AnimationValueMap) -> Self {
         let len = animation_value_map.len();
         let mut declarations = Vec::with_capacity(len);
@@ -687,7 +705,6 @@ impl PropertyDeclarationBlock {
 
     /// Returns true if the declaration block has a CSSWideKeyword for the given
     /// property.
-    #[cfg(feature = "gecko")]
     pub fn has_css_wide_keyword(&self, property: &PropertyId) -> bool {
         if let Some(id) = property.longhand_id() {
             if !self.longhands.contains(id) {
@@ -727,9 +744,7 @@ impl PropertyDeclarationBlock {
 
         builder.build()
     }
-}
 
-impl PropertyDeclarationBlock {
     /// Like the method on ToCss, but without the type parameter to avoid
     /// accidentally monomorphizing this large function multiple times for
     /// different writers.
@@ -1061,50 +1076,49 @@ where
 
 /// A helper to parse the style attribute of an element, in order for this to be
 /// shared between Servo and Gecko.
-pub fn parse_style_attribute<R>(
+///
+/// Inline because we call this cross-crate.
+#[inline]
+pub fn parse_style_attribute(
     input: &str,
     url_data: &UrlExtraData,
-    error_reporter: &R,
+    error_reporter: Option<&ParseErrorReporter>,
     quirks_mode: QuirksMode,
-) -> PropertyDeclarationBlock
-where
-    R: ParseErrorReporter
-{
+) -> PropertyDeclarationBlock {
     let context = ParserContext::new(
         Origin::Author,
         url_data,
         Some(CssRuleType::Style),
         ParsingMode::DEFAULT,
         quirks_mode,
+        error_reporter,
     );
 
-    let error_context = ParserErrorContext { error_reporter: error_reporter };
     let mut input = ParserInput::new(input);
-    parse_property_declaration_list(&context, &error_context, &mut Parser::new(&mut input))
+    parse_property_declaration_list(&context, &mut Parser::new(&mut input))
 }
 
 /// Parse a given property declaration. Can result in multiple
 /// `PropertyDeclaration`s when expanding a shorthand, for example.
 ///
 /// This does not attempt to parse !important at all.
-pub fn parse_one_declaration_into<R>(
+#[inline]
+pub fn parse_one_declaration_into(
     declarations: &mut SourcePropertyDeclaration,
     id: PropertyId,
     input: &str,
     url_data: &UrlExtraData,
-    error_reporter: &R,
+    error_reporter: Option<&ParseErrorReporter>,
     parsing_mode: ParsingMode,
     quirks_mode: QuirksMode
-) -> Result<(), ()>
-where
-    R: ParseErrorReporter
-{
+) -> Result<(), ()> {
     let context = ParserContext::new(
         Origin::Author,
         url_data,
         Some(CssRuleType::Style),
         parsing_mode,
         quirks_mode,
+        error_reporter,
     );
 
     let mut input = ParserInput::new(input);
@@ -1115,9 +1129,10 @@ where
     }).map_err(|err| {
         let location = err.location;
         let error = ContextualParseError::UnsupportedPropertyDeclaration(
-            parser.slice_from(start_position), err);
-        let error_context = ParserErrorContext { error_reporter: error_reporter };
-        context.log_css_error(&error_context, location, error);
+            parser.slice_from(start_position),
+            err,
+        );
+        context.log_css_error(location, error);
     })
 }
 
@@ -1177,14 +1192,10 @@ impl<'a, 'b, 'i> DeclarationParser<'i> for PropertyDeclarationParser<'a, 'b> {
 
 /// Parse a list of property declarations and return a property declaration
 /// block.
-pub fn parse_property_declaration_list<R>(
+pub fn parse_property_declaration_list(
     context: &ParserContext,
-    error_context: &ParserErrorContext<R>,
     input: &mut Parser,
-) -> PropertyDeclarationBlock
-where
-    R: ParseErrorReporter
-{
+) -> PropertyDeclarationBlock {
     let mut declarations = SourcePropertyDeclaration::new();
     let mut block = PropertyDeclarationBlock::new();
     let parser = PropertyDeclarationParser {
@@ -1212,7 +1223,7 @@ where
 
                 let location = error.location;
                 let error = ContextualParseError::UnsupportedPropertyDeclaration(slice, error);
-                context.log_css_error(error_context, location, error);
+                context.log_css_error(location, error);
             }
         }
     }
diff --git a/components/style/properties/helpers/animated_properties.mako.rs b/components/style/properties/helpers/animated_properties.mako.rs
index de0e48c782d..7a34cc4ade4 100644
--- a/components/style/properties/helpers/animated_properties.mako.rs
+++ b/components/style/properties/helpers/animated_properties.mako.rs
@@ -25,7 +25,7 @@ use servo_arc::Arc;
 use smallvec::SmallVec;
 use std::{cmp, ptr};
 use std::mem::{self, ManuallyDrop};
-#[cfg(feature = "gecko")] use hash::FnvHashMap;
+use hash::FnvHashMap;
 use super::ComputedValues;
 use values::CSSFloat;
 use values::animated::{Animate, Procedure, ToAnimatedValue, ToAnimatedZero};
@@ -229,8 +229,8 @@ impl AnimatedProperty {
 /// A collection of AnimationValue that were composed on an element.
 /// This HashMap stores the values that are the last AnimationValue to be
 /// composed for each TransitionProperty.
-#[cfg(feature = "gecko")]
 pub type AnimationValueMap = FnvHashMap<LonghandId, AnimationValue>;
+
 #[cfg(feature = "gecko")]
 unsafe impl HasFFI for AnimationValueMap {
     type FFIType = RawServoAnimationValueMap;
diff --git a/components/style/properties/longhand/background.mako.rs b/components/style/properties/longhands/background.mako.rs
index 9bb4e03e523..9bb4e03e523 100644
--- a/components/style/properties/longhand/background.mako.rs
+++ b/components/style/properties/longhands/background.mako.rs
diff --git a/components/style/properties/longhand/border.mako.rs b/components/style/properties/longhands/border.mako.rs
index 9bb3dbcec28..9bb3dbcec28 100644
--- a/components/style/properties/longhand/border.mako.rs
+++ b/components/style/properties/longhands/border.mako.rs
diff --git a/components/style/properties/longhand/box.mako.rs b/components/style/properties/longhands/box.mako.rs
index aea51fed766..ce04a0a66d2 100644
--- a/components/style/properties/longhand/box.mako.rs
+++ b/components/style/properties/longhands/box.mako.rs
@@ -606,8 +606,9 @@ ${helpers.single_keyword("-moz-appearance",
                             scalethumb-horizontal scalethumbstart scalethumbtick scalethumb-vertical scale-vertical
                             scrollbar scrollbar-horizontal scrollbar-small scrollbar-vertical scrollbarbutton-down
                             scrollbarbutton-left scrollbarbutton-right scrollbarbutton-up scrollbarthumb-horizontal
-                            scrollbarthumb-vertical scrollbartrack-horizontal scrollbartrack-vertical searchfield
-                            separator spinner spinner-downbutton spinner-textfield spinner-upbutton splitter statusbar
+                            scrollbarthumb-vertical scrollbartrack-horizontal scrollbartrack-vertical scrollcorner
+                            searchfield separator
+                            spinner spinner-downbutton spinner-textfield spinner-upbutton splitter statusbar
                             statusbarpanel tab tabpanel tabpanels tab-scroll-arrow-back tab-scroll-arrow-forward
                             textfield textfield-multiline toolbar toolbarbutton toolbarbutton-dropdown toolbargripper
                             toolbox tooltip treeheader treeheadercell treeheadersortarrow treeitem treeline treetwisty
diff --git a/components/style/properties/longhand/color.mako.rs b/components/style/properties/longhands/color.mako.rs
index a4d1830190a..a4d1830190a 100644
--- a/components/style/properties/longhand/color.mako.rs
+++ b/components/style/properties/longhands/color.mako.rs
diff --git a/components/style/properties/longhand/column.mako.rs b/components/style/properties/longhands/column.mako.rs
index 7a97c3f41e3..7a97c3f41e3 100644
--- a/components/style/properties/longhand/column.mako.rs
+++ b/components/style/properties/longhands/column.mako.rs
diff --git a/components/style/properties/longhand/counters.mako.rs b/components/style/properties/longhands/counters.mako.rs
index ececf58310f..ececf58310f 100644
--- a/components/style/properties/longhand/counters.mako.rs
+++ b/components/style/properties/longhands/counters.mako.rs
diff --git a/components/style/properties/longhand/effects.mako.rs b/components/style/properties/longhands/effects.mako.rs
index 674340c391a..674340c391a 100644
--- a/components/style/properties/longhand/effects.mako.rs
+++ b/components/style/properties/longhands/effects.mako.rs
diff --git a/components/style/properties/longhand/font.mako.rs b/components/style/properties/longhands/font.mako.rs
index 69f95532c16..69f95532c16 100644
--- a/components/style/properties/longhand/font.mako.rs
+++ b/components/style/properties/longhands/font.mako.rs
diff --git a/components/style/properties/longhand/inherited_box.mako.rs b/components/style/properties/longhands/inherited_box.mako.rs
index 23dfe7fef5c..23dfe7fef5c 100644
--- a/components/style/properties/longhand/inherited_box.mako.rs
+++ b/components/style/properties/longhands/inherited_box.mako.rs
diff --git a/components/style/properties/longhand/inherited_svg.mako.rs b/components/style/properties/longhands/inherited_svg.mako.rs
index b3bc12b1367..b3bc12b1367 100644
--- a/components/style/properties/longhand/inherited_svg.mako.rs
+++ b/components/style/properties/longhands/inherited_svg.mako.rs
diff --git a/components/style/properties/longhand/inherited_table.mako.rs b/components/style/properties/longhands/inherited_table.mako.rs
index 4f55d9b1fa5..4f55d9b1fa5 100644
--- a/components/style/properties/longhand/inherited_table.mako.rs
+++ b/components/style/properties/longhands/inherited_table.mako.rs
diff --git a/components/style/properties/longhand/inherited_text.mako.rs b/components/style/properties/longhands/inherited_text.mako.rs
index 62819a78cbc..62819a78cbc 100644
--- a/components/style/properties/longhand/inherited_text.mako.rs
+++ b/components/style/properties/longhands/inherited_text.mako.rs
diff --git a/components/style/properties/longhand/inherited_ui.mako.rs b/components/style/properties/longhands/inherited_ui.mako.rs
index 9718e33a84d..9718e33a84d 100644
--- a/components/style/properties/longhand/inherited_ui.mako.rs
+++ b/components/style/properties/longhands/inherited_ui.mako.rs
diff --git a/components/style/properties/longhand/list.mako.rs b/components/style/properties/longhands/list.mako.rs
index 5ed1ea44831..5ed1ea44831 100644
--- a/components/style/properties/longhand/list.mako.rs
+++ b/components/style/properties/longhands/list.mako.rs
diff --git a/components/style/properties/longhand/margin.mako.rs b/components/style/properties/longhands/margin.mako.rs
index 1a964bcbb74..1a964bcbb74 100644
--- a/components/style/properties/longhand/margin.mako.rs
+++ b/components/style/properties/longhands/margin.mako.rs
diff --git a/components/style/properties/longhand/outline.mako.rs b/components/style/properties/longhands/outline.mako.rs
index 9446745ec3e..9446745ec3e 100644
--- a/components/style/properties/longhand/outline.mako.rs
+++ b/components/style/properties/longhands/outline.mako.rs
diff --git a/components/style/properties/longhand/padding.mako.rs b/components/style/properties/longhands/padding.mako.rs
index 3d2467c0ca0..3d2467c0ca0 100644
--- a/components/style/properties/longhand/padding.mako.rs
+++ b/components/style/properties/longhands/padding.mako.rs
diff --git a/components/style/properties/longhand/position.mako.rs b/components/style/properties/longhands/position.mako.rs
index a99cebfdba9..a99cebfdba9 100644
--- a/components/style/properties/longhand/position.mako.rs
+++ b/components/style/properties/longhands/position.mako.rs
diff --git a/components/style/properties/longhand/svg.mako.rs b/components/style/properties/longhands/svg.mako.rs
index 6d7bf803f1e..6d7bf803f1e 100644
--- a/components/style/properties/longhand/svg.mako.rs
+++ b/components/style/properties/longhands/svg.mako.rs
diff --git a/components/style/properties/longhand/table.mako.rs b/components/style/properties/longhands/table.mako.rs
index 2af39e1d6e3..2af39e1d6e3 100644
--- a/components/style/properties/longhand/table.mako.rs
+++ b/components/style/properties/longhands/table.mako.rs
diff --git a/components/style/properties/longhand/text.mako.rs b/components/style/properties/longhands/text.mako.rs
index 613ed6c5f67..613ed6c5f67 100644
--- a/components/style/properties/longhand/text.mako.rs
+++ b/components/style/properties/longhands/text.mako.rs
diff --git a/components/style/properties/longhand/ui.mako.rs b/components/style/properties/longhands/ui.mako.rs
index 13a940b2b96..13a940b2b96 100644
--- a/components/style/properties/longhand/ui.mako.rs
+++ b/components/style/properties/longhands/ui.mako.rs
diff --git a/components/style/properties/longhand/xul.mako.rs b/components/style/properties/longhands/xul.mako.rs
index 15b8a695411..15b8a695411 100644
--- a/components/style/properties/longhand/xul.mako.rs
+++ b/components/style/properties/longhands/xul.mako.rs
diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index 4d18e0ca634..b6a8879e106 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -97,29 +97,9 @@ macro_rules! expanded {
 /// A module with all the code for longhand properties.
 #[allow(missing_docs)]
 pub mod longhands {
-    <%include file="/longhand/background.mako.rs" />
-    <%include file="/longhand/border.mako.rs" />
-    <%include file="/longhand/box.mako.rs" />
-    <%include file="/longhand/color.mako.rs" />
-    <%include file="/longhand/column.mako.rs" />
-    <%include file="/longhand/counters.mako.rs" />
-    <%include file="/longhand/effects.mako.rs" />
-    <%include file="/longhand/font.mako.rs" />
-    <%include file="/longhand/inherited_box.mako.rs" />
-    <%include file="/longhand/inherited_table.mako.rs" />
-    <%include file="/longhand/inherited_text.mako.rs" />
-    <%include file="/longhand/inherited_ui.mako.rs" />
-    <%include file="/longhand/list.mako.rs" />
-    <%include file="/longhand/margin.mako.rs" />
-    <%include file="/longhand/outline.mako.rs" />
-    <%include file="/longhand/padding.mako.rs" />
-    <%include file="/longhand/position.mako.rs" />
-    <%include file="/longhand/table.mako.rs" />
-    <%include file="/longhand/text.mako.rs" />
-    <%include file="/longhand/ui.mako.rs" />
-    <%include file="/longhand/inherited_svg.mako.rs" />
-    <%include file="/longhand/svg.mako.rs" />
-    <%include file="/longhand/xul.mako.rs" />
+    % for style_struct in data.style_structs:
+    include!("${repr(os.path.join(OUT_DIR, 'longhands/{}.rs'.format(style_struct.name_lower)))[1:-1]}");
+    % endfor
 }
 
 macro_rules! unwrap_or_initial {
@@ -137,23 +117,37 @@ pub mod shorthands {
     use style_traits::{ParseError, StyleParseErrorKind};
     use values::specified;
 
-    <%include file="/shorthand/serialize.mako.rs" />
-    <%include file="/shorthand/background.mako.rs" />
-    <%include file="/shorthand/border.mako.rs" />
-    <%include file="/shorthand/box.mako.rs" />
-    <%include file="/shorthand/column.mako.rs" />
-    <%include file="/shorthand/font.mako.rs" />
-    <%include file="/shorthand/inherited_text.mako.rs" />
-    <%include file="/shorthand/list.mako.rs" />
-    <%include file="/shorthand/margin.mako.rs" />
-    <%include file="/shorthand/mask.mako.rs" />
-    <%include file="/shorthand/outline.mako.rs" />
-    <%include file="/shorthand/padding.mako.rs" />
-    <%include file="/shorthand/position.mako.rs" />
-    <%include file="/shorthand/inherited_svg.mako.rs" />
-    <%include file="/shorthand/text.mako.rs" />
-
-    // We don't defined the 'all' shorthand using the regular helpers:shorthand
+    use style_traits::{CssWriter, ToCss};
+    use values::specified::{BorderStyle, Color};
+    use std::fmt::{self, Write};
+
+    fn serialize_directional_border<W, I,>(
+        dest: &mut CssWriter<W>,
+        width: &I,
+        style: &BorderStyle,
+        color: &Color,
+    ) -> fmt::Result
+    where
+        W: Write,
+        I: ToCss,
+    {
+        width.to_css(dest)?;
+        // FIXME(emilio): Should we really serialize the border style if it's
+        // `solid`?
+        dest.write_str(" ")?;
+        style.to_css(dest)?;
+        if *color != Color::CurrentColor {
+            dest.write_str(" ")?;
+            color.to_css(dest)?;
+        }
+        Ok(())
+    }
+
+    % for style_struct in data.style_structs:
+    include!("${repr(os.path.join(OUT_DIR, 'shorthands/{}.rs'.format(style_struct.name_lower)))[1:-1]}");
+    % endfor
+
+    // We didn't define the 'all' shorthand using the regular helpers:shorthand
     // mechanism, since it causes some very large types to be generated.
     //
     // Also, make sure logical properties appear before its physical
@@ -1448,6 +1442,7 @@ impl UnparsedValue {
                 None,
                 ParsingMode::DEFAULT,
                 quirks_mode,
+                None,
             );
 
             let mut input = ParserInput::new(&css);
@@ -3852,7 +3847,7 @@ where
         }
         % if category_to_cascade_now == "early":
             let writing_mode =
-                WritingMode::new(context.builder.get_inheritedbox());
+                WritingMode::new(context.builder.get_inherited_box());
             context.builder.writing_mode = writing_mode;
 
             let mut _skip_font_family = false;
diff --git a/components/style/properties/shorthand/serialize.mako.rs b/components/style/properties/shorthand/serialize.mako.rs
deleted file mode 100644
index afcbe3c488b..00000000000
--- a/components/style/properties/shorthand/serialize.mako.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-use style_traits::{CssWriter, ToCss};
-use values::specified::{BorderStyle, Color};
-use std::fmt::{self, Write};
-
-fn serialize_directional_border<W, I,>(
-    dest: &mut CssWriter<W>,
-    width: &I,
-    style: &BorderStyle,
-    color: &Color,
-) -> fmt::Result
-where
-    W: Write,
-    I: ToCss,
-{
-    width.to_css(dest)?;
-    dest.write_str(" ")?;
-    style.to_css(dest)?;
-    if *color != Color::CurrentColor {
-        dest.write_str(" ")?;
-        color.to_css(dest)?;
-    }
-    Ok(())
-}
diff --git a/components/style/properties/shorthand/background.mako.rs b/components/style/properties/shorthands/background.mako.rs
index b16c9918a24..b16c9918a24 100644
--- a/components/style/properties/shorthand/background.mako.rs
+++ b/components/style/properties/shorthands/background.mako.rs
diff --git a/components/style/properties/shorthand/border.mako.rs b/components/style/properties/shorthands/border.mako.rs
index 056096353bc..056096353bc 100644
--- a/components/style/properties/shorthand/border.mako.rs
+++ b/components/style/properties/shorthands/border.mako.rs
diff --git a/components/style/properties/shorthand/box.mako.rs b/components/style/properties/shorthands/box.mako.rs
index 842dfbd7229..842dfbd7229 100644
--- a/components/style/properties/shorthand/box.mako.rs
+++ b/components/style/properties/shorthands/box.mako.rs
diff --git a/components/style/properties/shorthand/column.mako.rs b/components/style/properties/shorthands/column.mako.rs
index cdd05dc786b..cdd05dc786b 100644
--- a/components/style/properties/shorthand/column.mako.rs
+++ b/components/style/properties/shorthands/column.mako.rs
diff --git a/components/style/properties/shorthand/font.mako.rs b/components/style/properties/shorthands/font.mako.rs
index a53f899851c..a53f899851c 100644
--- a/components/style/properties/shorthand/font.mako.rs
+++ b/components/style/properties/shorthands/font.mako.rs
diff --git a/components/style/properties/shorthand/inherited_svg.mako.rs b/components/style/properties/shorthands/inherited_svg.mako.rs
index 09c533a708b..09c533a708b 100644
--- a/components/style/properties/shorthand/inherited_svg.mako.rs
+++ b/components/style/properties/shorthands/inherited_svg.mako.rs
diff --git a/components/style/properties/shorthand/inherited_text.mako.rs b/components/style/properties/shorthands/inherited_text.mako.rs
index 98ded998bb1..98ded998bb1 100644
--- a/components/style/properties/shorthand/inherited_text.mako.rs
+++ b/components/style/properties/shorthands/inherited_text.mako.rs
diff --git a/components/style/properties/shorthand/list.mako.rs b/components/style/properties/shorthands/list.mako.rs
index 67e141f5ac6..67e141f5ac6 100644
--- a/components/style/properties/shorthand/list.mako.rs
+++ b/components/style/properties/shorthands/list.mako.rs
diff --git a/components/style/properties/shorthand/margin.mako.rs b/components/style/properties/shorthands/margin.mako.rs
index 07b6ba6bbed..07b6ba6bbed 100644
--- a/components/style/properties/shorthand/margin.mako.rs
+++ b/components/style/properties/shorthands/margin.mako.rs
diff --git a/components/style/properties/shorthand/outline.mako.rs b/components/style/properties/shorthands/outline.mako.rs
index 14b935f3bfd..14b935f3bfd 100644
--- a/components/style/properties/shorthand/outline.mako.rs
+++ b/components/style/properties/shorthands/outline.mako.rs
diff --git a/components/style/properties/shorthand/padding.mako.rs b/components/style/properties/shorthands/padding.mako.rs
index 592048cf56f..592048cf56f 100644
--- a/components/style/properties/shorthand/padding.mako.rs
+++ b/components/style/properties/shorthands/padding.mako.rs
diff --git a/components/style/properties/shorthand/position.mako.rs b/components/style/properties/shorthands/position.mako.rs
index 19ca0cf1916..19ca0cf1916 100644
--- a/components/style/properties/shorthand/position.mako.rs
+++ b/components/style/properties/shorthands/position.mako.rs
diff --git a/components/style/properties/shorthand/mask.mako.rs b/components/style/properties/shorthands/svg.mako.rs
index aa73c77e46b..aa73c77e46b 100644
--- a/components/style/properties/shorthand/mask.mako.rs
+++ b/components/style/properties/shorthands/svg.mako.rs
diff --git a/components/style/properties/shorthand/text.mako.rs b/components/style/properties/shorthands/text.mako.rs
index 18a0786494d..18a0786494d 100644
--- a/components/style/properties/shorthand/text.mako.rs
+++ b/components/style/properties/shorthands/text.mako.rs
diff --git a/components/style/servo/media_queries.rs b/components/style/servo/media_queries.rs
index 2ab4edca611..336971f98df 100644
--- a/components/style/servo/media_queries.rs
+++ b/components/style/servo/media_queries.rs
@@ -24,7 +24,7 @@ use values::computed::font::FontSize;
 /// is displayed in.
 ///
 /// This is the struct against which media queries are evaluated.
-#[derive(MallocSizeOf)]
+#[derive(Debug, MallocSizeOf)]
 pub struct Device {
     /// The current media type used by de device.
     media_type: MediaType,
diff --git a/components/style/sharing/mod.rs b/components/style/sharing/mod.rs
index 314e9877083..d6148d16b49 100644
--- a/components/style/sharing/mod.rs
+++ b/components/style/sharing/mod.rs
@@ -815,7 +815,11 @@ impl<E: TElement> StyleSharingCache<E> {
         Some(candidate.element.borrow_data().unwrap().share_styles())
     }
 
-    /// Attempts to find an element in the cache with the given primary rule node and parent.
+    /// Attempts to find an element in the cache with the given primary rule
+    /// node and parent.
+    ///
+    /// FIXME(emilio): re-measure this optimization, and remove if it's not very
+    /// useful... It's probably not worth the complexity / obscure bugs.
     pub fn lookup_by_rules(
         &mut self,
         shared_context: &SharedStyleContext,
@@ -841,7 +845,15 @@ impl<E: TElement> StyleSharingCache<E> {
             if style.visited_rules() != visited_rules {
                 return None;
             }
-
+            // NOTE(emilio): We only need to check name / namespace because we
+            // do name-dependent style adjustments, like the display: contents
+            // to display: none adjustment.
+            if target.namespace() != candidate.element.namespace() {
+                return None;
+            }
+            if target.local_name() != candidate.element.local_name() {
+                return None;
+            }
             // Rule nodes and styles are computed independent of the element's
             // actual visitedness, but at the end of the cascade (in
             // `adjust_for_visited`) we do store the visitedness as a flag in
@@ -853,6 +865,7 @@ impl<E: TElement> StyleSharingCache<E> {
             // FIXME(jryans): This seems like it breaks the constant time
             // requirements of visited, assuming we get a cache hit on only one
             // of unvisited vs. visited.
+            // TODO(emilio): We no longer have such a flag, remove this check.
             if target.is_visited_link() != candidate.element.is_visited_link() {
                 return None;
             }
diff --git a/components/style/style_adjuster.rs b/components/style/style_adjuster.rs
index 8bbc40ca8c6..754abab0993 100644
--- a/components/style/style_adjuster.rs
+++ b/components/style/style_adjuster.rs
@@ -19,6 +19,14 @@ use properties::longhands::position::computed_value::T as Position;
 /// NOTE(emilio): If new adjustments are introduced that depend on reset
 /// properties of the parent, you may need tweaking the
 /// `ChildCascadeRequirement` code in `matching.rs`.
+///
+/// NOTE(emilio): Also, if new adjustments are introduced that break the
+/// following invariant:
+///
+///   Given same tag name, namespace, rules and parent style, two elements would
+///   end up with exactly the same style.
+///
+/// Then you need to adjust the lookup_by_rules conditions in the sharing cache.
 pub struct StyleAdjuster<'a, 'b: 'a> {
     style: &'a mut StyleBuilder<'b>,
 }
@@ -248,8 +256,8 @@ impl<'a, 'b: 'a> StyleAdjuster<'a, 'b> {
         use computed_values::text_combine_upright::T as TextCombineUpright;
         use computed_values::writing_mode::T as WritingMode;
 
-        let writing_mode = self.style.get_inheritedbox().clone_writing_mode();
-        let text_combine_upright = self.style.get_inheritedtext().clone_text_combine_upright();
+        let writing_mode = self.style.get_inherited_box().clone_writing_mode();
+        let text_combine_upright = self.style.get_inherited_text().clone_text_combine_upright();
 
         if writing_mode != WritingMode::HorizontalTb &&
             text_combine_upright == TextCombineUpright::All
@@ -258,7 +266,7 @@ impl<'a, 'b: 'a> StyleAdjuster<'a, 'b> {
                 .flags
                 .insert(ComputedValueFlags::IS_TEXT_COMBINED);
             self.style
-                .mutate_inheritedbox()
+                .mutate_inherited_box()
                 .set_writing_mode(WritingMode::HorizontalTb);
         }
     }
@@ -297,8 +305,8 @@ impl<'a, 'b: 'a> StyleAdjuster<'a, 'b> {
     /// <https://lists.w3.org/Archives/Public/www-style/2017Mar/0045.html>
     /// <https://github.com/servo/servo/issues/15754>
     fn adjust_for_writing_mode(&mut self, layout_parent_style: &ComputedValues) {
-        let our_writing_mode = self.style.get_inheritedbox().clone_writing_mode();
-        let parent_writing_mode = layout_parent_style.get_inheritedbox().clone_writing_mode();
+        let our_writing_mode = self.style.get_inherited_box().clone_writing_mode();
+        let parent_writing_mode = layout_parent_style.get_inherited_box().clone_writing_mode();
 
         if our_writing_mode != parent_writing_mode &&
             self.style.get_box().clone_display() == Display::Inline
@@ -488,13 +496,13 @@ impl<'a, 'b: 'a> StyleAdjuster<'a, 'b> {
             return;
         }
 
-        match self.style.get_inheritedtext().clone_text_align() {
+        match self.style.get_inherited_text().clone_text_align() {
             TextAlign::MozLeft | TextAlign::MozCenter | TextAlign::MozRight => {},
             _ => return,
         }
 
         self.style
-            .mutate_inheritedtext()
+            .mutate_inherited_text()
             .set_text_align(TextAlign::Start)
     }
 
@@ -508,8 +516,8 @@ impl<'a, 'b: 'a> StyleAdjuster<'a, 'b> {
         use values::computed::text::TextDecorationsInEffect;
 
         let decorations_in_effect = TextDecorationsInEffect::from_style(&self.style);
-        if self.style.get_inheritedtext().text_decorations_in_effect != decorations_in_effect {
-            self.style.mutate_inheritedtext().text_decorations_in_effect = decorations_in_effect;
+        if self.style.get_inherited_text().text_decorations_in_effect != decorations_in_effect {
+            self.style.mutate_inherited_text().text_decorations_in_effect = decorations_in_effect;
         }
     }
 
diff --git a/components/style/stylesheets/font_feature_values_rule.rs b/components/style/stylesheets/font_feature_values_rule.rs
index 71fa8227928..8ce16e2ccf9 100644
--- a/components/style/stylesheets/font_feature_values_rule.rs
+++ b/components/style/stylesheets/font_feature_values_rule.rs
@@ -10,12 +10,12 @@ use Atom;
 use cssparser::{AtRuleParser, AtRuleType, BasicParseErrorKind, CowRcStr};
 use cssparser::{DeclarationListParser, DeclarationParser, Parser};
 use cssparser::{QualifiedRuleParser, RuleListParser, SourceLocation, Token};
-use error_reporting::{ContextualParseError, ParseErrorReporter};
+use error_reporting::ContextualParseError;
 #[cfg(feature = "gecko")]
 use gecko_bindings::bindings::Gecko_AppendFeatureValueHashEntry;
 #[cfg(feature = "gecko")]
 use gecko_bindings::structs::{self, gfxFontFeatureValueSet, nsTArray};
-use parser::{Parse, ParserContext, ParserErrorContext};
+use parser::{Parse, ParserContext};
 use shared_lock::{SharedRwLockReadGuard, ToCssWithGuard};
 use std::fmt::{self, Write};
 use str::CssStringWriter;
@@ -267,27 +267,24 @@ macro_rules! font_feature_values_blocks {
             }
 
             /// Parses a `FontFeatureValuesRule`.
-            pub fn parse<R>(context: &ParserContext,
-                            error_context: &ParserErrorContext<R>,
-                            input: &mut Parser,
-                            family_names: Vec<FamilyName>,
-                            location: SourceLocation)
-                            -> FontFeatureValuesRule
-                where R: ParseErrorReporter
-            {
+            pub fn parse(
+                context: &ParserContext,
+                input: &mut Parser,
+                family_names: Vec<FamilyName>,
+                location: SourceLocation,
+            ) -> Self {
                 let mut rule = FontFeatureValuesRule::new(family_names, location);
 
                 {
                     let mut iter = RuleListParser::new_for_nested_rule(input, FontFeatureValuesRuleParser {
                         context: context,
-                        error_context: error_context,
                         rule: &mut rule,
                     });
                     while let Some(result) = iter.next() {
                         if let Err((error, slice)) = result {
                             let location = error.location;
                             let error = ContextualParseError::UnsupportedRule(slice, error);
-                            context.log_css_error(error_context, location, error);
+                            context.log_css_error(location, error);
                         }
                     }
                 }
@@ -398,20 +395,19 @@ macro_rules! font_feature_values_blocks {
         /// }
         /// <feature-type> = @stylistic | @historical-forms | @styleset |
         /// @character-variant | @swash | @ornaments | @annotation
-        struct FontFeatureValuesRuleParser<'a, R: 'a> {
+        struct FontFeatureValuesRuleParser<'a> {
             context: &'a ParserContext<'a>,
-            error_context: &'a ParserErrorContext<'a, R>,
             rule: &'a mut FontFeatureValuesRule,
         }
 
         /// Default methods reject all qualified rules.
-        impl<'a, 'i, R: ParseErrorReporter> QualifiedRuleParser<'i> for FontFeatureValuesRuleParser<'a, R> {
+        impl<'a, 'i> QualifiedRuleParser<'i> for FontFeatureValuesRuleParser<'a> {
             type Prelude = ();
             type QualifiedRule = ();
             type Error = StyleParseErrorKind<'i>;
         }
 
-        impl<'a, 'i, R: ParseErrorReporter> AtRuleParser<'i> for FontFeatureValuesRuleParser<'a, R> {
+        impl<'a, 'i> AtRuleParser<'i> for FontFeatureValuesRuleParser<'a> {
             type PreludeNoBlock = ();
             type PreludeBlock = BlockType;
             type AtRule = ();
@@ -450,7 +446,7 @@ macro_rules! font_feature_values_blocks {
                                     let error = ContextualParseError::UnsupportedKeyframePropertyDeclaration(
                                         slice, error
                                     );
-                                    self.context.log_css_error(self.error_context, location, error);
+                                    self.context.log_css_error(location, error);
                                 }
                             }
                         },
diff --git a/components/style/stylesheets/keyframes_rule.rs b/components/style/stylesheets/keyframes_rule.rs
index 5f39267ac7b..a0cb5fa0b1d 100644
--- a/components/style/stylesheets/keyframes_rule.rs
+++ b/components/style/stylesheets/keyframes_rule.rs
@@ -6,8 +6,8 @@
 
 use cssparser::{AtRuleParser, CowRcStr, Parser, ParserInput, QualifiedRuleParser, RuleListParser};
 use cssparser::{parse_one_rule, DeclarationListParser, DeclarationParser, SourceLocation, Token};
-use error_reporting::{ContextualParseError, NullReporter, ParseErrorReporter};
-use parser::{ParserContext, ParserErrorContext};
+use error_reporting::ContextualParseError;
+use parser::ParserContext;
 use properties::{DeclarationSource, Importance, PropertyDeclaration};
 use properties::{LonghandId, PropertyDeclarationBlock, PropertyId};
 use properties::{PropertyDeclarationId, SourcePropertyDeclaration};
@@ -211,7 +211,6 @@ impl Keyframe {
         lock: &SharedRwLock,
     ) -> Result<Arc<Locked<Self>>, ParseError<'i>> {
         let url_data = parent_stylesheet_contents.url_data.read();
-        let error_reporter = NullReporter;
         let namespaces = parent_stylesheet_contents.namespaces.read();
         let mut context = ParserContext::new(
             parent_stylesheet_contents.origin,
@@ -219,10 +218,8 @@ impl Keyframe {
             Some(CssRuleType::Keyframe),
             ParsingMode::DEFAULT,
             parent_stylesheet_contents.quirks_mode,
+            None,
         );
-        let error_context = ParserErrorContext {
-            error_reporter: &error_reporter,
-        };
         context.namespaces = Some(&*namespaces);
         let mut input = ParserInput::new(css);
         let mut input = Parser::new(&mut input);
@@ -230,7 +227,6 @@ impl Keyframe {
         let mut declarations = SourcePropertyDeclaration::new();
         let mut rule_parser = KeyframeListParser {
             context: &context,
-            error_context: &error_context,
             shared_lock: &lock,
             declarations: &mut declarations,
         };
@@ -477,23 +473,18 @@ impl KeyframesAnimation {
 /// 40%, 60%, 100% {
 ///     width: 100%;
 /// }
-struct KeyframeListParser<'a, R: 'a> {
+struct KeyframeListParser<'a> {
     context: &'a ParserContext<'a>,
-    error_context: &'a ParserErrorContext<'a, R>,
     shared_lock: &'a SharedRwLock,
     declarations: &'a mut SourcePropertyDeclaration,
 }
 
 /// Parses a keyframe list from CSS input.
-pub fn parse_keyframe_list<R>(
+pub fn parse_keyframe_list(
     context: &ParserContext,
-    error_context: &ParserErrorContext<R>,
     input: &mut Parser,
     shared_lock: &SharedRwLock,
-) -> Vec<Arc<Locked<Keyframe>>>
-where
-    R: ParseErrorReporter,
-{
+) -> Vec<Arc<Locked<Keyframe>>> {
     debug_assert!(
         context.namespaces.is_some(),
         "Parsing a keyframe list from a context without namespaces?"
@@ -504,7 +495,6 @@ where
         input,
         KeyframeListParser {
             context: context,
-            error_context: error_context,
             shared_lock: shared_lock,
             declarations: &mut declarations,
         },
@@ -512,7 +502,7 @@ where
         .collect()
 }
 
-impl<'a, 'i, R> AtRuleParser<'i> for KeyframeListParser<'a, R> {
+impl<'a, 'i> AtRuleParser<'i> for KeyframeListParser<'a> {
     type PreludeNoBlock = ();
     type PreludeBlock = ();
     type AtRule = Arc<Locked<Keyframe>>;
@@ -525,7 +515,7 @@ struct KeyframeSelectorParserPrelude {
     source_location: SourceLocation,
 }
 
-impl<'a, 'i, R: ParseErrorReporter> QualifiedRuleParser<'i> for KeyframeListParser<'a, R> {
+impl<'a, 'i> QualifiedRuleParser<'i> for KeyframeListParser<'a> {
     type Prelude = KeyframeSelectorParserPrelude;
     type QualifiedRule = Arc<Locked<Keyframe>>;
     type Error = StyleParseErrorKind<'i>;
@@ -547,8 +537,7 @@ impl<'a, 'i, R: ParseErrorReporter> QualifiedRuleParser<'i> for KeyframeListPars
                     input.slice_from(start_position),
                     e.clone(),
                 );
-                self.context
-                    .log_css_error(self.error_context, location, error);
+                self.context.log_css_error(location, error);
                 Err(e)
             },
         }
@@ -585,7 +574,7 @@ impl<'a, 'i, R: ParseErrorReporter> QualifiedRuleParser<'i> for KeyframeListPars
                     let location = error.location;
                     let error =
                         ContextualParseError::UnsupportedKeyframePropertyDeclaration(slice, error);
-                    context.log_css_error(self.error_context, location, error);
+                    context.log_css_error(location, error);
                 },
             }
             // `parse_important` is not called here, `!important` is not allowed in keyframe blocks.
diff --git a/components/style/stylesheets/mod.rs b/components/style/stylesheets/mod.rs
index 2d6539c08b4..e3641f3e515 100644
--- a/components/style/stylesheets/mod.rs
+++ b/components/style/stylesheets/mod.rs
@@ -24,10 +24,9 @@ pub mod supports_rule;
 pub mod viewport_rule;
 
 use cssparser::{parse_one_rule, Parser, ParserInput};
-use error_reporting::NullReporter;
 #[cfg(feature = "gecko")]
 use malloc_size_of::{MallocSizeOfOps, MallocUnconditionalShallowSizeOf};
-use parser::{ParserContext, ParserErrorContext};
+use parser::ParserContext;
 use servo_arc::Arc;
 use shared_lock::{DeepCloneParams, DeepCloneWithLock, Locked};
 use shared_lock::{SharedRwLock, SharedRwLockReadGuard, ToCssWithGuard};
@@ -62,22 +61,52 @@ pub type UrlExtraData = ::servo_url::ServoUrl;
 
 /// Extra data that the backend may need to resolve url values.
 #[cfg(feature = "gecko")]
-pub type UrlExtraData =
-    ::gecko_bindings::sugar::refptr::RefPtr<::gecko_bindings::structs::URLExtraData>;
+#[derive(Clone, PartialEq)]
+pub struct UrlExtraData(
+    pub ::gecko_bindings::sugar::refptr::RefPtr<::gecko_bindings::structs::URLExtraData>
+);
 
 #[cfg(feature = "gecko")]
 impl UrlExtraData {
-    /// Returns a string for the url.
+    /// True if this URL scheme is chrome.
+    #[inline]
+    pub fn is_chrome(&self) -> bool {
+        self.0.mIsChrome
+    }
+
+    /// Create a reference to this `UrlExtraData` from a reference to pointer.
     ///
-    /// Unimplemented currently.
-    pub fn as_str(&self) -> &str {
-        // TODO
-        "(stylo: not supported)"
+    /// The pointer must be valid and non null.
+    ///
+    /// This method doesn't touch refcount.
+    #[inline]
+    pub unsafe fn from_ptr_ref(ptr: &*mut ::gecko_bindings::structs::URLExtraData) -> &Self {
+        ::std::mem::transmute(ptr)
     }
+}
 
-    /// True if this URL scheme is chrome.
-    pub fn is_chrome(&self) -> bool {
-        self.mIsChrome
+#[cfg(feature = "gecko")]
+impl fmt::Debug for UrlExtraData {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        use gecko_bindings::{structs, bindings};
+
+        struct DebugURI(*mut structs::nsIURI);
+        impl fmt::Debug for DebugURI {
+            fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                use nsstring::nsCString;
+                let mut spec = nsCString::new();
+                unsafe {
+                    bindings::Gecko_nsIURI_Debug(self.0, &mut spec);
+                }
+                spec.fmt(formatter)
+            }
+        }
+
+        formatter.debug_struct("URLExtraData")
+            .field("is_chrome", &self.is_chrome())
+            .field("base", &DebugURI(self.0.mBaseURI.raw::<structs::nsIURI>()))
+            .field("referrer", &DebugURI(self.0.mReferrer.raw::<structs::nsIURI>()))
+            .finish()
     }
 }
 
@@ -228,13 +257,13 @@ impl CssRule {
         loader: Option<&StylesheetLoader>,
     ) -> Result<Self, RulesMutateError> {
         let url_data = parent_stylesheet_contents.url_data.read();
-        let error_reporter = NullReporter;
         let context = ParserContext::new(
             parent_stylesheet_contents.origin,
             &url_data,
             None,
             ParsingMode::DEFAULT,
             parent_stylesheet_contents.quirks_mode,
+            None,
         );
 
         let mut input = ParserInput::new(css);
@@ -246,9 +275,6 @@ impl CssRule {
         let mut rule_parser = TopLevelRuleParser {
             stylesheet_origin: parent_stylesheet_contents.origin,
             context,
-            error_context: ParserErrorContext {
-                error_reporter: &error_reporter,
-            },
             shared_lock: &shared_lock,
             loader,
             state,
diff --git a/components/style/stylesheets/rule_parser.rs b/components/style/stylesheets/rule_parser.rs
index 259130dd89b..41d87aa07a4 100644
--- a/components/style/stylesheets/rule_parser.rs
+++ b/components/style/stylesheets/rule_parser.rs
@@ -8,10 +8,10 @@ use {Namespace, Prefix};
 use counter_style::{parse_counter_style_body, parse_counter_style_name_definition};
 use cssparser::{AtRuleParser, AtRuleType, Parser, QualifiedRuleParser, RuleListParser};
 use cssparser::{BasicParseError, BasicParseErrorKind, CowRcStr, SourceLocation};
-use error_reporting::{ContextualParseError, ParseErrorReporter};
+use error_reporting::ContextualParseError;
 use font_face::parse_font_face_block;
 use media_queries::MediaList;
-use parser::{Parse, ParserContext, ParserErrorContext};
+use parser::{Parse, ParserContext};
 use properties::parse_property_declaration_list;
 use selector_parser::{SelectorImpl, SelectorParser};
 use selectors::SelectorList;
@@ -40,7 +40,7 @@ pub struct InsertRuleContext<'a> {
 }
 
 /// The parser for the top-level rules in a stylesheet.
-pub struct TopLevelRuleParser<'a, R: 'a> {
+pub struct TopLevelRuleParser<'a> {
     /// The origin of the stylesheet we're parsing.
     pub stylesheet_origin: Origin,
     /// A reference to the lock we need to use to create rules.
@@ -52,8 +52,6 @@ pub struct TopLevelRuleParser<'a, R: 'a> {
     /// This won't contain any namespaces, and only nested parsers created with
     /// `ParserContext::new_with_rule_type` will.
     pub context: ParserContext<'a>,
-    /// The context required for reporting parse errors.
-    pub error_context: ParserErrorContext<'a, R>,
     /// The current state of the parser.
     pub state: State,
     /// Whether we have tried to parse was invalid due to being in the wrong
@@ -68,13 +66,12 @@ pub struct TopLevelRuleParser<'a, R: 'a> {
     pub insert_rule_context: Option<InsertRuleContext<'a>>,
 }
 
-impl<'b, R> TopLevelRuleParser<'b, R> {
-    fn nested<'a: 'b>(&'a self) -> NestedRuleParser<'a, 'b, R> {
+impl<'b> TopLevelRuleParser<'b> {
+    fn nested<'a: 'b>(&'a self) -> NestedRuleParser<'a, 'b> {
         NestedRuleParser {
             stylesheet_origin: self.stylesheet_origin,
             shared_lock: self.shared_lock,
             context: &self.context,
-            error_context: &self.error_context,
             namespaces: &self.namespaces,
         }
     }
@@ -176,7 +173,7 @@ pub enum AtRuleNonBlockPrelude {
     Namespace(Option<Prefix>, Namespace, SourceLocation),
 }
 
-impl<'a, 'i, R: ParseErrorReporter> AtRuleParser<'i> for TopLevelRuleParser<'a, R> {
+impl<'a, 'i> AtRuleParser<'i> for TopLevelRuleParser<'a> {
     type PreludeNoBlock = AtRuleNonBlockPrelude;
     type PreludeBlock = AtRuleBlockPrelude;
     type AtRule = CssRule;
@@ -197,11 +194,7 @@ impl<'a, 'i, R: ParseErrorReporter> AtRuleParser<'i> for TopLevelRuleParser<'a,
                 let url_string = input.expect_url_or_string()?.as_ref().to_owned();
                 let url = CssUrl::parse_from_string(url_string, &self.context);
 
-                let media = MediaList::parse(
-                    &self.context,
-                    input,
-                    self.error_context.error_reporter,
-                );
+                let media = MediaList::parse(&self.context, input);
                 let media = Arc::new(self.shared_lock.wrap(media));
 
                 let prelude = AtRuleNonBlockPrelude::Import(url, media, location);
@@ -296,7 +289,7 @@ pub struct QualifiedRuleParserPrelude {
     source_location: SourceLocation,
 }
 
-impl<'a, 'i, R: ParseErrorReporter> QualifiedRuleParser<'i> for TopLevelRuleParser<'a, R> {
+impl<'a, 'i> QualifiedRuleParser<'i> for TopLevelRuleParser<'a> {
     type Prelude = QualifiedRuleParserPrelude;
     type QualifiedRule = CssRule;
     type Error = StyleParseErrorKind<'i>;
@@ -327,27 +320,29 @@ impl<'a, 'i, R: ParseErrorReporter> QualifiedRuleParser<'i> for TopLevelRulePars
 }
 
 #[derive(Clone)] // shallow, relatively cheap .clone
-struct NestedRuleParser<'a, 'b: 'a, R: 'b> {
+struct NestedRuleParser<'a, 'b: 'a> {
     stylesheet_origin: Origin,
     shared_lock: &'a SharedRwLock,
     context: &'a ParserContext<'b>,
-    error_context: &'a ParserErrorContext<'b, R>,
     namespaces: &'a Namespaces,
 }
 
-impl<'a, 'b, R: ParseErrorReporter> NestedRuleParser<'a, 'b, R> {
+impl<'a, 'b> NestedRuleParser<'a, 'b> {
     fn parse_nested_rules(
         &mut self,
         input: &mut Parser,
         rule_type: CssRuleType,
     ) -> Arc<Locked<CssRules>> {
-        let context = ParserContext::new_with_rule_type(self.context, rule_type, self.namespaces);
+        let context = ParserContext::new_with_rule_type(
+            self.context,
+            rule_type,
+            self.namespaces,
+        );
 
         let nested_parser = NestedRuleParser {
             stylesheet_origin: self.stylesheet_origin,
             shared_lock: self.shared_lock,
             context: &context,
-            error_context: &self.error_context,
             namespaces: self.namespaces,
         };
 
@@ -359,8 +354,7 @@ impl<'a, 'b, R: ParseErrorReporter> NestedRuleParser<'a, 'b, R> {
                 Err((error, slice)) => {
                     let location = error.location;
                     let error = ContextualParseError::InvalidRule(slice, error);
-                    self.context
-                        .log_css_error(self.error_context, location, error);
+                    self.context.log_css_error(location, error);
                 },
             }
         }
@@ -368,7 +362,7 @@ impl<'a, 'b, R: ParseErrorReporter> NestedRuleParser<'a, 'b, R> {
     }
 }
 
-impl<'a, 'b, 'i, R: ParseErrorReporter> AtRuleParser<'i> for NestedRuleParser<'a, 'b, R> {
+impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
     type PreludeNoBlock = AtRuleNonBlockPrelude;
     type PreludeBlock = AtRuleBlockPrelude;
     type AtRule = CssRule;
@@ -383,11 +377,7 @@ impl<'a, 'b, 'i, R: ParseErrorReporter> AtRuleParser<'i> for NestedRuleParser<'a
 
         match_ignore_ascii_case! { &*name,
             "media" => {
-                let media_queries = MediaList::parse(
-                    self.context,
-                    input,
-                    self.error_context.error_reporter,
-                );
+                let media_queries = MediaList::parse(self.context, input);
                 let arc = Arc::new(self.shared_lock.wrap(media_queries));
                 Ok(AtRuleType::WithBlock(AtRuleBlockPrelude::Media(arc, location)))
             },
@@ -473,7 +463,7 @@ impl<'a, 'b, 'i, R: ParseErrorReporter> AtRuleParser<'i> for NestedRuleParser<'a
                 );
 
                 Ok(CssRule::FontFace(Arc::new(self.shared_lock.wrap(
-                    parse_font_face_block(&context, self.error_context, input, location).into(),
+                    parse_font_face_block(&context, input, location).into(),
                 ))))
             },
             AtRuleBlockPrelude::FontFeatureValues(family_names, location) => {
@@ -486,7 +476,6 @@ impl<'a, 'b, 'i, R: ParseErrorReporter> AtRuleParser<'i> for NestedRuleParser<'a
                 Ok(CssRule::FontFeatureValues(Arc::new(self.shared_lock.wrap(
                     FontFeatureValuesRule::parse(
                         &context,
-                        self.error_context,
                         input,
                         family_names,
                         location,
@@ -505,7 +494,6 @@ impl<'a, 'b, 'i, R: ParseErrorReporter> AtRuleParser<'i> for NestedRuleParser<'a
                         parse_counter_style_body(
                             name,
                             &context,
-                            self.error_context,
                             input,
                             location,
                         )?.into(),
@@ -544,7 +532,7 @@ impl<'a, 'b, 'i, R: ParseErrorReporter> AtRuleParser<'i> for NestedRuleParser<'a
                 );
 
                 Ok(CssRule::Viewport(Arc::new(self.shared_lock.wrap(
-                    ViewportRule::parse(&context, self.error_context, input)?,
+                    ViewportRule::parse(&context, input)?,
                 ))))
             },
             AtRuleBlockPrelude::Keyframes(name, vendor_prefix, source_location) => {
@@ -559,7 +547,6 @@ impl<'a, 'b, 'i, R: ParseErrorReporter> AtRuleParser<'i> for NestedRuleParser<'a
                         name,
                         keyframes: parse_keyframe_list(
                             &context,
-                            self.error_context,
                             input,
                             self.shared_lock,
                         ),
@@ -576,7 +563,7 @@ impl<'a, 'b, 'i, R: ParseErrorReporter> AtRuleParser<'i> for NestedRuleParser<'a
                 );
 
                 let declarations =
-                    parse_property_declaration_list(&context, self.error_context, input);
+                    parse_property_declaration_list(&context, input);
                 Ok(CssRule::Page(Arc::new(self.shared_lock.wrap(PageRule {
                     block: Arc::new(self.shared_lock.wrap(declarations)),
                     source_location,
@@ -598,7 +585,7 @@ impl<'a, 'b, 'i, R: ParseErrorReporter> AtRuleParser<'i> for NestedRuleParser<'a
     }
 }
 
-impl<'a, 'b, 'i, R: ParseErrorReporter> QualifiedRuleParser<'i> for NestedRuleParser<'a, 'b, R> {
+impl<'a, 'b, 'i> QualifiedRuleParser<'i> for NestedRuleParser<'a, 'b> {
     type Prelude = QualifiedRuleParserPrelude;
     type QualifiedRule = CssRule;
     type Error = StyleParseErrorKind<'i>;
@@ -627,7 +614,7 @@ impl<'a, 'b, 'i, R: ParseErrorReporter> QualifiedRuleParser<'i> for NestedRulePa
         let context =
             ParserContext::new_with_rule_type(self.context, CssRuleType::Style, self.namespaces);
 
-        let declarations = parse_property_declaration_list(&context, self.error_context, input);
+        let declarations = parse_property_declaration_list(&context, input);
         Ok(CssRule::Style(Arc::new(self.shared_lock.wrap(StyleRule {
             selectors: prelude.selectors,
             block: Arc::new(self.shared_lock.wrap(declarations)),
diff --git a/components/style/stylesheets/stylesheet.rs b/components/style/stylesheets/stylesheet.rs
index b33875a149c..ee24a918c73 100644
--- a/components/style/stylesheets/stylesheet.rs
+++ b/components/style/stylesheets/stylesheet.rs
@@ -13,7 +13,7 @@ use invalidation::media_queries::{MediaListKey, ToMediaListKey};
 use malloc_size_of::{MallocSizeOfOps, MallocUnconditionalShallowSizeOf};
 use media_queries::{Device, MediaList};
 use parking_lot::RwLock;
-use parser::{ParserContext, ParserErrorContext};
+use parser::ParserContext;
 use servo_arc::Arc;
 use shared_lock::{DeepCloneParams, DeepCloneWithLock, Locked, SharedRwLock, SharedRwLockReadGuard};
 use std::mem;
@@ -69,13 +69,13 @@ pub struct StylesheetContents {
 impl StylesheetContents {
     /// Parse a given CSS string, with a given url-data, origin, and
     /// quirks mode.
-    pub fn from_str<R: ParseErrorReporter>(
+    pub fn from_str(
         css: &str,
         url_data: UrlExtraData,
         origin: Origin,
         shared_lock: &SharedRwLock,
         stylesheet_loader: Option<&StylesheetLoader>,
-        error_reporter: &R,
+        error_reporter: Option<&ParseErrorReporter>,
         quirks_mode: QuirksMode,
         line_number_offset: u32,
     ) -> Self {
@@ -137,7 +137,7 @@ impl DeepCloneWithLock for StylesheetContents {
             url_data: RwLock::new((*self.url_data.read()).clone()),
             namespaces: RwLock::new((*self.namespaces.read()).clone()),
             source_map_url: RwLock::new((*self.source_map_url.read()).clone()),
-            source_url: RwLock::new((*self.source_map_url.read()).clone()),
+            source_url: RwLock::new((*self.source_url.read()).clone()),
         }
     }
 }
@@ -176,7 +176,7 @@ macro_rules! rule_filter {
 }
 
 /// A trait to represent a given stylesheet in a document.
-pub trait StylesheetInDocument {
+pub trait StylesheetInDocument : ::std::fmt::Debug {
     /// Get the stylesheet origin.
     fn origin(&self, guard: &SharedRwLockReadGuard) -> Origin;
 
@@ -263,7 +263,7 @@ impl StylesheetInDocument for Stylesheet {
 
 /// A simple wrapper over an `Arc<Stylesheet>`, with pointer comparison, and
 /// suitable for its use in a `StylesheetSet`.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
 pub struct DocumentStyleSheet(
     #[cfg_attr(feature = "servo", ignore_malloc_size_of = "Arc")] pub Arc<Stylesheet>,
@@ -306,18 +306,16 @@ impl StylesheetInDocument for DocumentStyleSheet {
 
 impl Stylesheet {
     /// Updates an empty stylesheet from a given string of text.
-    pub fn update_from_str<R>(
+    pub fn update_from_str(
         existing: &Stylesheet,
         css: &str,
         url_data: UrlExtraData,
         stylesheet_loader: Option<&StylesheetLoader>,
-        error_reporter: &R,
+        error_reporter: Option<&ParseErrorReporter>,
         line_number_offset: u32,
-    ) where
-        R: ParseErrorReporter,
-    {
+    ) {
         let namespaces = RwLock::new(Namespaces::default());
-        let (rules, source_map_url, source_url) = Stylesheet::parse_rules(
+        let (rules, source_map_url, source_url) = Self::parse_rules(
             css,
             &url_data,
             existing.contents.origin,
@@ -342,14 +340,14 @@ impl Stylesheet {
         *existing.contents.source_url.write() = source_url;
     }
 
-    fn parse_rules<R: ParseErrorReporter>(
+    fn parse_rules(
         css: &str,
         url_data: &UrlExtraData,
         origin: Origin,
         namespaces: &mut Namespaces,
         shared_lock: &SharedRwLock,
         stylesheet_loader: Option<&StylesheetLoader>,
-        error_reporter: &R,
+        error_reporter: Option<&ParseErrorReporter>,
         quirks_mode: QuirksMode,
         line_number_offset: u32,
     ) -> (Vec<CssRule>, Option<String>, Option<String>) {
@@ -357,16 +355,20 @@ impl Stylesheet {
         let mut input = ParserInput::new_with_line_number_offset(css, line_number_offset);
         let mut input = Parser::new(&mut input);
 
-        let context = ParserContext::new(origin, url_data, None, ParsingMode::DEFAULT, quirks_mode);
-
-        let error_context = ParserErrorContext { error_reporter };
+        let context = ParserContext::new(
+            origin,
+            url_data,
+            None,
+            ParsingMode::DEFAULT,
+            quirks_mode,
+            error_reporter,
+        );
 
         let rule_parser = TopLevelRuleParser {
             stylesheet_origin: origin,
             shared_lock,
             loader: stylesheet_loader,
             context,
-            error_context,
             state: State::Start,
             dom_error: None,
             insert_rule_context: None,
@@ -390,7 +392,6 @@ impl Stylesheet {
                         let location = error.location;
                         let error = ContextualParseError::InvalidRule(slice, error);
                         iter.parser.context.log_css_error(
-                            &iter.parser.error_context,
                             location,
                             error,
                         );
@@ -409,17 +410,17 @@ impl Stylesheet {
     ///
     /// Effectively creates a new stylesheet and forwards the hard work to
     /// `Stylesheet::update_from_str`.
-    pub fn from_str<R: ParseErrorReporter>(
+    pub fn from_str(
         css: &str,
         url_data: UrlExtraData,
         origin: Origin,
         media: Arc<Locked<MediaList>>,
         shared_lock: SharedRwLock,
         stylesheet_loader: Option<&StylesheetLoader>,
-        error_reporter: &R,
+        error_reporter: Option<&ParseErrorReporter>,
         quirks_mode: QuirksMode,
         line_number_offset: u32,
-    ) -> Stylesheet {
+    ) -> Self {
         let contents = StylesheetContents::from_str(
             css,
             url_data,
diff --git a/components/style/stylesheets/viewport_rule.rs b/components/style/stylesheets/viewport_rule.rs
index b159b65d35b..1fc6a988c7c 100644
--- a/components/style/stylesheets/viewport_rule.rs
+++ b/components/style/stylesheets/viewport_rule.rs
@@ -11,11 +11,11 @@ use app_units::Au;
 use context::QuirksMode;
 use cssparser::{parse_important, AtRuleParser, DeclarationListParser, DeclarationParser, Parser};
 use cssparser::CowRcStr;
-use error_reporting::{ContextualParseError, ParseErrorReporter};
+use error_reporting::ContextualParseError;
 use euclid::TypedSize2D;
 use font_metrics::get_metrics_provider_for_product;
 use media_queries::Device;
-use parser::{ParserContext, ParserErrorContext};
+use parser::ParserContext;
 use properties::StyleBuilder;
 use rule_cache::RuleCacheConditions;
 use selectors::parser::SelectorParseErrorKind;
@@ -355,15 +355,13 @@ fn is_whitespace_separator_or_equals(c: &char) -> bool {
 
 impl ViewportRule {
     /// Parse a single @viewport rule.
-    pub fn parse<'i, 't, R>(
+    ///
+    /// TODO(emilio): This could use the `Parse` trait now.
+    pub fn parse<'i, 't>(
         context: &ParserContext,
-        error_context: &ParserErrorContext<R>,
         input: &mut Parser<'i, 't>,
-    ) -> Result<Self, ParseError<'i>>
-    where
-        R: ParseErrorReporter,
-    {
-        let parser = ViewportRuleParser { context: context };
+    ) -> Result<Self, ParseError<'i>> {
+        let parser = ViewportRuleParser { context };
 
         let mut cascade = Cascade::new();
         let mut parser = DeclarationListParser::new(input, parser);
@@ -380,7 +378,7 @@ impl ViewportRule {
                         slice,
                         error,
                     );
-                    context.log_css_error(error_context, location, error);
+                    context.log_css_error(location, error);
                 },
             }
         }
diff --git a/components/style/stylist.rs b/components/style/stylist.rs
index e777921e668..aa5f77d0db4 100644
--- a/components/style/stylist.rs
+++ b/components/style/stylist.rs
@@ -75,6 +75,10 @@ impl UserAgentCascadeDataCache {
         Self { entries: vec![] }
     }
 
+    fn len(&self) -> usize {
+        self.entries.len()
+    }
+
     // FIXME(emilio): This may need to be keyed on quirks-mode too, though there
     // aren't class / id selectors on those sheets, usually, so it's probably
     // ok...
@@ -90,6 +94,7 @@ impl UserAgentCascadeDataCache {
         S: StylesheetInDocument + ToMediaListKey + PartialEq + 'static,
     {
         let mut key = EffectiveMediaQueryResults::new();
+        debug!("UserAgentCascadeDataCache::lookup({:?})", device);
         for sheet in sheets.clone() {
             CascadeData::collect_applicable_media_query_results_into(device, sheet, guard, &mut key)
         }
@@ -105,6 +110,8 @@ impl UserAgentCascadeDataCache {
             precomputed_pseudo_element_decls: PrecomputedPseudoElementDeclarations::default(),
         };
 
+        debug!("> Picking the slow path");
+
         for sheet in sheets {
             new_data.cascade_data.add_stylesheet(
                 device,
@@ -117,7 +124,6 @@ impl UserAgentCascadeDataCache {
         }
 
         let new_data = Arc::new(new_data);
-
         self.entries.push(new_data.clone());
         Ok(new_data)
     }
@@ -244,8 +250,8 @@ impl DocumentCascadeData {
                 let origin_sheets = flusher.origin_sheets(Origin::UserAgent);
                 let ua_cascade_data =
                     ua_cache.lookup(origin_sheets, device, quirks_mode, guards.ua_or_user)?;
-
                 ua_cache.expire_unused();
+                debug!("User agent data cache size {:?}", ua_cache.len());
                 self.user_agent = ua_cascade_data;
             }
         }
@@ -1085,7 +1091,7 @@ impl Stylist {
         guards: &StylesheetGuards,
         device: &Device,
     ) -> OriginSet {
-        debug!("Stylist::media_features_change_changed_style");
+        debug!("Stylist::media_features_change_changed_style {:?}", device);
 
         let mut origins = OriginSet::empty();
         let stylesheets = self.stylesheets.iter();
@@ -2145,16 +2151,19 @@ impl CascadeData {
             return;
         }
 
+        debug!(" + {:?}", stylesheet);
         results.saw_effective(stylesheet);
 
         for rule in stylesheet.effective_rules(device, guard) {
             match *rule {
                 CssRule::Import(ref lock) => {
                     let import_rule = lock.read_with(guard);
+                    debug!(" + {:?}", import_rule.stylesheet.media(guard));
                     results.saw_effective(import_rule);
                 },
                 CssRule::Media(ref lock) => {
                     let media_rule = lock.read_with(guard);
+                    debug!(" + {:?}", media_rule.media_queries.read_with(guard));
                     results.saw_effective(media_rule);
                 },
                 _ => {},
@@ -2346,8 +2355,10 @@ impl CascadeData {
 
         if effective_now != effective_then {
             debug!(
-                " > Stylesheet changed -> {}, {}",
-                effective_then, effective_now
+                " > Stylesheet {:?} changed -> {}, {}",
+                stylesheet.media(guard),
+                effective_then,
+                effective_now
             );
             return false;
         }
@@ -2382,8 +2393,10 @@ impl CascadeData {
                         .was_effective(import_rule);
                     if effective_now != effective_then {
                         debug!(
-                            " > @import rule changed {} -> {}",
-                            effective_then, effective_now
+                            " > @import rule {:?} changed {} -> {}",
+                            import_rule.stylesheet.media(guard),
+                            effective_then,
+                            effective_now
                         );
                         return false;
                     }
@@ -2401,8 +2414,10 @@ impl CascadeData {
 
                     if effective_now != effective_then {
                         debug!(
-                            " > @media rule changed {} -> {}",
-                            effective_then, effective_now
+                            " > @media rule {:?} changed {} -> {}",
+                            mq,
+                            effective_then,
+                            effective_now
                         );
                         return false;
                     }
diff --git a/components/style/values/computed/text.rs b/components/style/values/computed/text.rs
index f2bcf11fe62..b41ecdb7e67 100644
--- a/components/style/values/computed/text.rs
+++ b/components/style/values/computed/text.rs
@@ -107,7 +107,7 @@ impl TextDecorationsInEffect {
         let mut result = match style.get_box().clone_display() {
             Display::InlineBlock | Display::InlineTable => Self::default(),
             _ => style
-                .get_parent_inheritedtext()
+                .get_parent_inherited_text()
                 .text_decorations_in_effect
                 .clone(),
         };
diff --git a/components/style/values/specified/text.rs b/components/style/values/specified/text.rs
index 70947ac0826..ef0e66672d0 100644
--- a/components/style/values/specified/text.rs
+++ b/components/style/values/specified/text.rs
@@ -514,7 +514,7 @@ impl ToComputedValue for TextAlign {
                 }
                 let parent = _context
                     .builder
-                    .get_parent_inheritedtext()
+                    .get_parent_inherited_text()
                     .clone_text_align();
                 let ltr = _context.builder.inherited_writing_mode().is_bidi_ltr();
                 match (parent, ltr) {
@@ -529,7 +529,7 @@ impl ToComputedValue for TextAlign {
             TextAlign::MozCenterOrInherit => {
                 let parent = _context
                     .builder
-                    .get_parent_inheritedtext()
+                    .get_parent_inherited_text()
                     .clone_text_align();
                 if parent == TextAlignKeyword::Start {
                     TextAlignKeyword::Center
@@ -653,7 +653,7 @@ impl ToComputedValue for TextEmphasisStyle {
     fn to_computed_value(&self, context: &Context) -> Self::ComputedValue {
         match *self {
             TextEmphasisStyle::Keyword(ref keyword) => {
-                let default_shape = if context.style().get_inheritedbox().clone_writing_mode() ==
+                let default_shape = if context.style().get_inherited_box().clone_writing_mode() ==
                     SpecifiedWritingMode::HorizontalTb
                 {
                     TextEmphasisShapeKeyword::Circle
diff --git a/components/style_derive/to_css.rs b/components/style_derive/to_css.rs
index 471cf37b6de..83177f3c89f 100644
--- a/components/style_derive/to_css.rs
+++ b/components/style_derive/to_css.rs
@@ -231,6 +231,8 @@ pub struct CssInputAttrs {
 #[derive(Default, FromVariant)]
 pub struct CssVariantAttrs {
     pub function: Option<Override<String>>,
+    // Here because structs variants are also their whole type definition.
+    pub derive_debug: bool,
     pub comma: bool,
     pub dimension: bool,
     pub keyword: Option<String>,
diff --git a/tests/unit/style/lib.rs b/tests/unit/style/lib.rs
index d8e5464b75e..2c46bb65063 100644
--- a/tests/unit/style/lib.rs
+++ b/tests/unit/style/lib.rs
@@ -45,7 +45,7 @@ mod writing_modes {
     #[test]
     fn initial_writing_mode_is_empty() {
         assert_eq!(
-            WritingMode::new(INITIAL_SERVO_VALUES.get_inheritedbox()),
+            WritingMode::new(INITIAL_SERVO_VALUES.get_inherited_box()),
             WritingMode::empty(),
         )
     }
diff --git a/tests/unit/style/media_queries.rs b/tests/unit/style/media_queries.rs
index 58b878bfb8d..044dee3db72 100644
--- a/tests/unit/style/media_queries.rs
+++ b/tests/unit/style/media_queries.rs
@@ -2,7 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use cssparser::SourceLocation;
 use euclid::TypedScale;
 use euclid::TypedSize2D;
 use servo_arc::Arc;
@@ -10,7 +9,6 @@ use servo_url::ServoUrl;
 use std::borrow::ToOwned;
 use style::Atom;
 use style::context::QuirksMode;
-use style::error_reporting::{ParseErrorReporter, ContextualParseError};
 use style::media_queries::*;
 use style::servo::media_queries::*;
 use style::shared_lock::SharedRwLock;
@@ -18,18 +16,9 @@ use style::stylesheets::{AllRules, Stylesheet, StylesheetInDocument, Origin, Css
 use style::values::{CustomIdent, specified};
 use style_traits::ToCss;
 
-pub struct CSSErrorReporterTest;
-
-impl ParseErrorReporter for CSSErrorReporterTest {
-    fn report_error(&self,
-                    _url: &ServoUrl,
-                    _location: SourceLocation,
-                    _error: ContextualParseError) {
-    }
-}
-
 fn test_media_rule<F>(css: &str, callback: F)
-    where F: Fn(&MediaList, &str),
+where
+    F: Fn(&MediaList, &str),
 {
     let url = ServoUrl::parse("http://localhost").unwrap();
     let css_str = css.to_owned();
@@ -37,7 +26,7 @@ fn test_media_rule<F>(css: &str, callback: F)
     let media_list = Arc::new(lock.wrap(MediaList::empty()));
     let stylesheet = Stylesheet::from_str(
         css, url, Origin::Author, media_list, lock,
-        None, &CSSErrorReporterTest, QuirksMode::NoQuirks, 0);
+        None, None, QuirksMode::NoQuirks, 0);
     let dummy = Device::new(MediaType::screen(), TypedSize2D::new(200.0, 100.0), TypedScale::new(1.0));
     let mut rule_count = 0;
     let guard = stylesheet.shared_lock.read();
@@ -56,7 +45,7 @@ fn media_query_test(device: &Device, css: &str, expected_rule_count: usize) {
     let media_list = Arc::new(lock.wrap(MediaList::empty()));
     let ss = Stylesheet::from_str(
         css, url, Origin::Author, media_list, lock,
-        None, &CSSErrorReporterTest, QuirksMode::NoQuirks, 0);
+        None, None, QuirksMode::NoQuirks, 0);
     let mut rule_count = 0;
     ss.effective_style_rules(device, &ss.shared_lock.read(), |_| rule_count += 1);
     assert!(rule_count == expected_rule_count, css.to_owned());
diff --git a/tests/unit/style/parsing/length.rs b/tests/unit/style/parsing/length.rs
deleted file mode 100644
index 0d506926ad8..00000000000
--- a/tests/unit/style/parsing/length.rs
+++ /dev/null
@@ -1,49 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-use cssparser::{Parser, ParserInput};
-use parsing::parse;
-use style::context::QuirksMode;
-use style::parser::{Parse, ParserContext};
-use style::stylesheets::{CssRuleType, Origin};
-use style::values::specified::length::{AbsoluteLength, Length, NoCalcLength};
-use style_traits::{ParsingMode, ToCss};
-
-#[test]
-fn test_calc() {
-    assert!(parse(Length::parse, "calc(1px+ 2px)").is_err());
-    assert!(parse(Length::parse, "calc(calc(1px) + calc(1px + 4px))").is_ok());
-    assert!(parse(Length::parse, "calc( 1px + 2px )").is_ok());
-    assert!(parse(Length::parse, "calc(1px + 2px )").is_ok());
-    assert!(parse(Length::parse, "calc( 1px + 2px)").is_ok());
-    assert!(parse(Length::parse, "calc( 1px + 2px / ( 1 + 2 - 1))").is_ok());
-}
-
-#[test]
-fn test_length_literals() {
-    assert_roundtrip_with_context!(Length::parse, "0.33px", "0.33px");
-    assert_roundtrip_with_context!(Length::parse, "0.33in", "0.33in");
-    assert_roundtrip_with_context!(Length::parse, "0.33cm", "0.33cm");
-    assert_roundtrip_with_context!(Length::parse, "0.33mm", "0.33mm");
-    assert_roundtrip_with_context!(Length::parse, "0.33q", "0.33q");
-    assert_roundtrip_with_context!(Length::parse, "0.33pt", "0.33pt");
-    assert_roundtrip_with_context!(Length::parse, "0.33pc", "0.33pc");
-}
-
-#[test]
-fn test_parsing_modes() {
-    // In default length mode, non-zero lengths must have a unit.
-    assert!(parse(Length::parse, "1").is_err());
-
-    // In SVG length mode, non-zero lengths are assumed to be px.
-    let url = ::servo_url::ServoUrl::parse("http://localhost").unwrap();
-    let context = ParserContext::new(Origin::Author, &url,
-                                     Some(CssRuleType::Style), ParsingMode::ALLOW_UNITLESS_LENGTH,
-                                     QuirksMode::NoQuirks);
-    let mut input = ParserInput::new("1");
-    let mut parser = Parser::new(&mut input);
-    let result = Length::parse(&context, &mut parser);
-    assert!(result.is_ok());
-    assert_eq!(result.unwrap(), Length::NoCalc(NoCalcLength::Absolute(AbsoluteLength::Px(1.))));
-}
diff --git a/tests/unit/style/parsing/mod.rs b/tests/unit/style/parsing/mod.rs
index d89e76378f7..b75e3a7ce42 100644
--- a/tests/unit/style/parsing/mod.rs
+++ b/tests/unit/style/parsing/mod.rs
@@ -21,7 +21,7 @@ where F: Fn(&ParserContext, &mut Parser<'i, 't>) -> Result<T, ParseError<'i>> {
     let url = ::servo_url::ServoUrl::parse("http://localhost").unwrap();
     let context = ParserContext::new(Origin::Author, &url, Some(CssRuleType::Style),
                                      ParsingMode::DEFAULT,
-                                     QuirksMode::NoQuirks);
+                                     QuirksMode::NoQuirks, None);
     let mut parser = Parser::new(input);
     f(&context, &mut parser)
 }
@@ -111,7 +111,6 @@ mod column;
 mod effects;
 mod image;
 mod inherited_text;
-mod length;
 mod outline;
 mod position;
 mod selectors;
@@ -119,4 +118,3 @@ mod supports;
 mod text_overflow;
 mod transition_duration;
 mod transition_timing_function;
-mod value;
diff --git a/tests/unit/style/parsing/value.rs b/tests/unit/style/parsing/value.rs
deleted file mode 100644
index d464831f56b..00000000000
--- a/tests/unit/style/parsing/value.rs
+++ /dev/null
@@ -1,25 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-use cssparser::{Parser, ParserInput};
-use style::context::QuirksMode;
-use style::parser::ParserContext;
-use style::stylesheets::{CssRuleType, Origin};
-use style::values::specified::Number;
-use style_traits::ParsingMode;
-
-#[test]
-fn test_parsing_allo_all_numeric_values() {
-    // In SVG length mode, non-zero lengths are assumed to be px.
-    let url = ::servo_url::ServoUrl::parse("http://localhost").unwrap();
-    let context = ParserContext::new(Origin::Author, &url,
-                                     Some(CssRuleType::Style), ParsingMode::ALLOW_ALL_NUMERIC_VALUES,
-                                     QuirksMode::NoQuirks);
-    let mut input = ParserInput::new("-1");
-    let mut parser = Parser::new(&mut input);
-    let result = Number::parse_non_negative(&context, &mut parser);
-    assert!(result.is_ok());
-    assert_eq!(result.unwrap(), Number::new(-1.));
-}
-
diff --git a/tests/unit/style/properties/background.rs b/tests/unit/style/properties/background.rs
deleted file mode 100644
index 6c0b27a49fe..00000000000
--- a/tests/unit/style/properties/background.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-use properties::parse;
-use style::properties::longhands::background_size;
-
-#[test]
-fn background_size_should_reject_negative_values() {
-    assert!(parse(|c, _, i| background_size::parse(c, i), "-40% -40%").is_err());
-}
diff --git a/tests/unit/style/properties/mod.rs b/tests/unit/style/properties/mod.rs
index ccd4fdd7a0b..725aabc42a4 100644
--- a/tests/unit/style/properties/mod.rs
+++ b/tests/unit/style/properties/mod.rs
@@ -3,34 +3,32 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use cssparser::{Parser, ParserInput};
-use media_queries::CSSErrorReporterTest;
 use style::context::QuirksMode;
-use style::parser::{ParserContext, ParserErrorContext};
+use style::parser::ParserContext;
 use style::stylesheets::{CssRuleType, Origin};
 use style_traits::{ParsingMode, ParseError};
 
 fn parse<T, F>(f: F, s: &'static str) -> Result<T, ParseError<'static>>
-    where F: for<'t> Fn(&ParserContext,
-                        &ParserErrorContext<CSSErrorReporterTest>,
-                        &mut Parser<'static, 't>) -> Result<T, ParseError<'static>>
+where
+    F: for<'t> Fn(
+        &ParserContext,
+        &mut Parser<'static, 't>,
+    ) -> Result<T, ParseError<'static>>
 {
     let mut input = ParserInput::new(s);
     parse_input(f, &mut input)
 }
 
 fn parse_input<'i: 't, 't, T, F>(f: F, input: &'t mut ParserInput<'i>) -> Result<T, ParseError<'i>>
-    where F: Fn(&ParserContext,
-                &ParserErrorContext<CSSErrorReporterTest>,
-                &mut Parser<'i, 't>) -> Result<T, ParseError<'i>>
+where
+    F: Fn(&ParserContext, &mut Parser<'i, 't>) -> Result<T, ParseError<'i>>,
 {
     let url = ::servo_url::ServoUrl::parse("http://localhost").unwrap();
     let context = ParserContext::new(Origin::Author, &url, Some(CssRuleType::Style),
                                      ParsingMode::DEFAULT,
-                                     QuirksMode::NoQuirks);
-    let reporter = CSSErrorReporterTest;
-    let error_context = ParserErrorContext { error_reporter: &reporter };
+                                     QuirksMode::NoQuirks, None);
     let mut parser = Parser::new(input);
-    f(&context, &error_context, &mut parser)
+    f(&context, &mut parser)
 }
 
 macro_rules! assert_roundtrip_with_context {
@@ -38,7 +36,7 @@ macro_rules! assert_roundtrip_with_context {
         assert_roundtrip_with_context!($fun, $string, $string);
     };
     ($fun:expr, $input:expr, $output:expr) => {{
-        let serialized = parse(|context, _, i| {
+        let serialized = parse(|context, i| {
             let parsed = $fun(context, i)
                          .expect(&format!("Failed to parse {}", $input));
             let serialized = ToCss::to_css_string(&parsed);
@@ -47,7 +45,7 @@ macro_rules! assert_roundtrip_with_context {
         }, $input).unwrap();
 
         let mut input = ::cssparser::ParserInput::new(&serialized);
-        let unwrapped = parse_input(|context, _, i| {
+        let unwrapped = parse_input(|context, i| {
             let re_parsed = $fun(context, i)
                             .expect(&format!("Failed to parse serialization {}", $input));
             let re_serialized = ToCss::to_css_string(&re_parsed);
@@ -58,6 +56,5 @@ macro_rules! assert_roundtrip_with_context {
     }}
 }
 
-mod background;
 mod scaffolding;
 mod serialization;
diff --git a/tests/unit/style/properties/serialization.rs b/tests/unit/style/properties/serialization.rs
index e7b5689e05f..4ab79d25a2f 100644
--- a/tests/unit/style/properties/serialization.rs
+++ b/tests/unit/style/properties/serialization.rs
@@ -451,7 +451,7 @@ mod shorthand_serialization {
                 border-left: 4px solid; \
                 border-image: none;";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -503,7 +503,7 @@ mod shorthand_serialization {
                 background-origin: border-box; \
                 background-clip: padding-box;";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -527,7 +527,7 @@ mod shorthand_serialization {
                 background-origin: padding-box; \
                 background-clip: padding-box;";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -551,7 +551,7 @@ mod shorthand_serialization {
                 background-origin: border-box, padding-box; \
                 background-clip: padding-box, padding-box;";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -582,7 +582,7 @@ mod shorthand_serialization {
                 background-origin: border-box; \
                 background-clip: padding-box, padding-box;";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -596,7 +596,7 @@ mod shorthand_serialization {
             let block_text = "\
                 background-position-x: 30px;\
                 background-position-y: bottom 20px;";
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
             let serialization = block.to_css_string();
             assert_eq!(serialization, "background-position: left 30px bottom 20px;");
 
@@ -605,7 +605,7 @@ mod shorthand_serialization {
             let block_text = "\
                 background-position-x: center;\
                 background-position-y: 20px;";
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
             let serialization = block.to_css_string();
             assert_eq!(serialization, "background-position: center 20px;");
         }
@@ -691,7 +691,7 @@ mod shorthand_serialization {
                 animation-iteration-count: infinite;\
                 animation-play-state: paused;";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -710,7 +710,7 @@ mod shorthand_serialization {
                 animation-iteration-count: infinite, 2;\
                 animation-play-state: paused, running;";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -736,7 +736,7 @@ mod shorthand_serialization {
                 animation-iteration-count: infinite, 2; \
                 animation-play-state: paused, running;";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -753,7 +753,7 @@ mod shorthand_serialization {
                               animation-iteration-count: infinite, 2; \
                               animation-play-state: paused, running;";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -771,7 +771,7 @@ mod shorthand_serialization {
                               transition-delay: 4s; \
                               transition-timing-function: cubic-bezier(0.2, 5, 0.5, 2);";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -785,7 +785,7 @@ mod shorthand_serialization {
                               transition-delay: 4s, 5s; \
                               transition-timing-function: cubic-bezier(0.2, 5, 0.5, 2), ease;";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -807,7 +807,7 @@ mod shorthand_serialization {
                               transition-delay: 4s, 5s; \
                               transition-timing-function: cubic-bezier(0.2, 5, 0.5, 2), ease;";
 
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -820,7 +820,7 @@ mod shorthand_serialization {
                               transition-duration: 3s; \
                               transition-delay: 4s; \
                               transition-timing-function: steps(2, start);";
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -833,7 +833,7 @@ mod shorthand_serialization {
                               transition-duration: 3s; \
                               transition-delay: 4s; \
                               transition-timing-function: frames(2);";
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
 
@@ -846,7 +846,7 @@ mod shorthand_serialization {
         #[test]
         fn css_wide_keywords_should_be_parsed() {
             let block_text = "--a:inherit;";
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
             assert_eq!(serialization, "--a: inherit;");
@@ -855,7 +855,7 @@ mod shorthand_serialization {
         #[test]
         fn non_keyword_custom_property_should_be_unparsed() {
             let block_text = "--main-color: #06c;";
-            let block = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), block_text).unwrap();
+            let block = parse(|c, i| Ok(parse_property_declaration_list(c, i)), block_text).unwrap();
 
             let serialization = block.to_css_string();
             assert_eq!(serialization, block_text);
@@ -885,7 +885,7 @@ mod shorthand_serialization {
             let shadow_decl = BoxShadowList(vec![shadow_val]);
             properties.push(PropertyDeclaration::BoxShadow(shadow_decl));
             let shadow_css = "box-shadow: 1px 2px 3px 4px;";
-            let shadow = parse(|c, e, i| Ok(parse_property_declaration_list(c, e, i)), shadow_css).unwrap();
+            let shadow = parse(|c, i| Ok(parse_property_declaration_list(c, i)), shadow_css).unwrap();
 
             assert_eq!(shadow.to_css_string(), shadow_css);
         }
diff --git a/tests/unit/style/rule_tree/bench.rs b/tests/unit/style/rule_tree/bench.rs
index 54af9d39532..c1ea58f5248 100644
--- a/tests/unit/style/rule_tree/bench.rs
+++ b/tests/unit/style/rule_tree/bench.rs
@@ -55,7 +55,7 @@ fn parse_rules(css: &str) -> Vec<(StyleSource, CascadeLevel)> {
                                  media,
                                  lock,
                                  None,
-                                 &ErrorringErrorReporter,
+                                 Some(&ErrorringErrorReporter),
                                  QuirksMode::NoQuirks,
                                  0);
     let guard = s.shared_lock.read();
diff --git a/tests/unit/style/stylesheets.rs b/tests/unit/style/stylesheets.rs
index be4e2d9cbc1..632d51074fe 100644
--- a/tests/unit/style/stylesheets.rs
+++ b/tests/unit/style/stylesheets.rs
@@ -4,7 +4,6 @@
 
 use cssparser::{self, SourceLocation};
 use html5ever::{Namespace as NsAtom};
-use media_queries::CSSErrorReporterTest;
 use parking_lot::RwLock;
 use selectors::attr::*;
 use selectors::parser::*;
@@ -71,7 +70,7 @@ fn test_parse_stylesheet() {
     let lock = SharedRwLock::new();
     let media = Arc::new(lock.wrap(MediaList::empty()));
     let stylesheet = Stylesheet::from_str(css, url.clone(), Origin::UserAgent, media, lock,
-                                          None, &CSSErrorReporterTest, QuirksMode::NoQuirks, 0);
+                                          None, None, QuirksMode::NoQuirks, 0);
     let mut namespaces = Namespaces::default();
     namespaces.default = Some(ns!(html));
     let expected = Stylesheet {
@@ -345,7 +344,7 @@ fn test_report_error_stylesheet() {
     let lock = SharedRwLock::new();
     let media = Arc::new(lock.wrap(MediaList::empty()));
     Stylesheet::from_str(css, url.clone(), Origin::UserAgent, media, lock,
-                         None, &error_reporter, QuirksMode::NoQuirks, 5);
+                         None, Some(&error_reporter), QuirksMode::NoQuirks, 5);
 
     error_reporter.assert_messages_contain(&[
         (8, 18, "Unsupported property declaration: 'display: invalid;'"),
@@ -387,7 +386,7 @@ fn test_no_report_unrecognized_vendor_properties() {
     let lock = SharedRwLock::new();
     let media = Arc::new(lock.wrap(MediaList::empty()));
     Stylesheet::from_str(css, url, Origin::UserAgent, media, lock,
-                         None, &error_reporter, QuirksMode::NoQuirks, 0);
+                         None, Some(&error_reporter), QuirksMode::NoQuirks, 0);
 
     error_reporter.assert_messages_contain(&[
         (4, 31, "Unsupported property declaration: '-moz-background-color: red;'"),
@@ -406,7 +405,7 @@ fn test_source_map_url() {
         let lock = SharedRwLock::new();
         let media = Arc::new(lock.wrap(MediaList::empty()));
         let stylesheet = Stylesheet::from_str(test.0, url.clone(), Origin::UserAgent, media, lock,
-                                              None, &CSSErrorReporterTest, QuirksMode::NoQuirks,
+                                              None, None, QuirksMode::NoQuirks,
                                               0);
         let url_opt = stylesheet.contents.source_map_url.read();
         assert_eq!(*url_opt, test.1);
@@ -425,7 +424,7 @@ fn test_source_url() {
         let lock = SharedRwLock::new();
         let media = Arc::new(lock.wrap(MediaList::empty()));
         let stylesheet = Stylesheet::from_str(test.0, url.clone(), Origin::UserAgent, media, lock,
-                                              None, &CSSErrorReporterTest, QuirksMode::NoQuirks,
+                                              None, None, QuirksMode::NoQuirks,
                                               0);
         let url_opt = stylesheet.contents.source_url.read();
         assert_eq!(*url_opt, test.1);
diff --git a/tests/unit/style/viewport.rs b/tests/unit/style/viewport.rs
index 44759bed701..9243dbcb403 100644
--- a/tests/unit/style/viewport.rs
+++ b/tests/unit/style/viewport.rs
@@ -5,13 +5,12 @@
 use cssparser::{Parser, ParserInput};
 use euclid::TypedScale;
 use euclid::TypedSize2D;
-use media_queries::CSSErrorReporterTest;
 use servo_arc::Arc;
 use servo_config::prefs::{PREFS, PrefValue};
 use servo_url::ServoUrl;
 use style::context::QuirksMode;
 use style::media_queries::{Device, MediaList, MediaType};
-use style::parser::{ParserContext, ParserErrorContext};
+use style::parser::ParserContext;
 use style::shared_lock::{SharedRwLock, StylesheetGuards};
 use style::stylesheets::{CssRuleType, Stylesheet, StylesheetInDocument, Origin};
 use style::stylesheets::viewport_rule::*;
@@ -22,10 +21,10 @@ use style_traits::{ParsingMode, PinchZoomFactor};
 use style_traits::viewport::*;
 
 macro_rules! stylesheet {
-    ($css:expr, $origin:ident, $error_reporter:expr) => {
-        stylesheet!($css, $origin, $error_reporter, SharedRwLock::new())
+    ($css:expr, $origin:ident) => {
+        stylesheet!($css, $origin, SharedRwLock::new())
     };
-    ($css:expr, $origin:ident, $error_reporter:expr, $shared_lock:expr) => {
+    ($css:expr, $origin:ident, $shared_lock:expr) => {
         Arc::new(Stylesheet::from_str(
             $css,
             ServoUrl::parse("http://localhost").unwrap(),
@@ -33,7 +32,7 @@ macro_rules! stylesheet {
             Arc::new($shared_lock.wrap(MediaList::empty())),
             $shared_lock,
             None,
-            &$error_reporter,
+            None,
             QuirksMode::NoQuirks,
             0
         ))
@@ -46,7 +45,7 @@ fn test_viewport_rule<F>(css: &str,
     where F: Fn(&Vec<ViewportDescriptorDeclaration>, &str)
 {
     PREFS.set("layout.viewport.enabled", PrefValue::Boolean(true));
-    let stylesheet = stylesheet!(css, Author, CSSErrorReporterTest);
+    let stylesheet = stylesheet!(css, Author);
     let mut rule_count = 0;
     stylesheet.effective_viewport_rules(&device, &stylesheet.shared_lock.read(), |rule| {
         rule_count += 1;
@@ -259,15 +258,15 @@ fn cascading_within_viewport_rule() {
 fn multiple_stylesheets_cascading() {
     PREFS.set("layout.viewport.enabled", PrefValue::Boolean(true));
     let device = Device::new(MediaType::screen(), TypedSize2D::new(800., 600.), TypedScale::new(1.0));
-    let error_reporter = CSSErrorReporterTest;
     let shared_lock = SharedRwLock::new();
     let stylesheets = vec![
         stylesheet!("@viewport { min-width: 100px; min-height: 100px; zoom: 1; }",
-                    UserAgent, error_reporter, shared_lock.clone()),
+                    UserAgent,
+                    shared_lock.clone()),
         stylesheet!("@viewport { min-width: 200px; min-height: 200px; }",
-                    User, error_reporter, shared_lock.clone()),
+                    User, shared_lock.clone()),
         stylesheet!("@viewport { min-width: 300px; }",
-                    Author, error_reporter, shared_lock.clone())
+                    Author, shared_lock.clone())
     ];
 
     let declarations = Cascade::from_stylesheets(
@@ -282,11 +281,11 @@ fn multiple_stylesheets_cascading() {
 
     let stylesheets = vec![
         stylesheet!("@viewport { min-width: 100px !important; }",
-                    UserAgent, error_reporter, shared_lock.clone()),
+                    UserAgent, shared_lock.clone()),
         stylesheet!("@viewport { min-width: 200px !important; min-height: 200px !important; }",
-                    User, error_reporter, shared_lock.clone()),
+                    User, shared_lock.clone()),
         stylesheet!("@viewport { min-width: 300px !important; min-height: 300px !important; zoom: 3 !important; }",
-                    Author, error_reporter, shared_lock.clone())
+                    Author, shared_lock.clone())
     ];
     let declarations = Cascade::from_stylesheets(
         stylesheets.iter().map(|s| (&**s, Origin::Author)),
@@ -304,12 +303,11 @@ fn constrain_viewport() {
     let url = ServoUrl::parse("http://localhost").unwrap();
     let context = ParserContext::new(Origin::Author, &url, Some(CssRuleType::Viewport),
                                      ParsingMode::DEFAULT,
-                                     QuirksMode::NoQuirks);
-    let error_context = ParserErrorContext { error_reporter: &CSSErrorReporterTest };
+                                     QuirksMode::NoQuirks, None);
 
     macro_rules! from_css {
         ($css:expr) => {
-            &ViewportRule::parse(&context, &error_context, &mut Parser::new(&mut $css)).unwrap()
+            &ViewportRule::parse(&context, &mut Parser::new(&mut $css)).unwrap()
         }
     }