Auto merge of #15463 - Manishearth:buncha-props, r=mbrubeck

stylo: Implement a bunch of properties

r? @mbrubeck or @heycam

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/15463)
<!-- Reviewable:end -->

20 files changed, 451 insertions, 246 deletions

diff --git a/components/layout/display_list_builder.rs b/components/layout/display_list_builder.rs
index 1285d5cef7a..4dc72f20301 100644
--- a/components/layout/display_list_builder.rs
+++ b/components/layout/display_list_builder.rs
@@ -1176,10 +1176,11 @@ impl FragmentDisplayListBuilding for Fragment {
     fn adjust_clip_for_style(&self,
                              parent_clip: &mut ClippingRegion,
                              stacking_relative_border_box: &Rect<Au>) {
+        use style::values::Either;
         // Account for `clip` per CSS 2.1 § 11.1.2.
         let style_clip_rect = match (self.style().get_box().position,
-                                     self.style().get_effects().clip.0) {
-            (position::T::absolute, Some(style_clip_rect)) => style_clip_rect,
+                                     self.style().get_effects().clip) {
+            (position::T::absolute, Either::First(style_clip_rect)) => style_clip_rect,
             _ => return,
         };
 
diff --git a/components/style/gecko_bindings/sugar/ns_t_array.rs b/components/style/gecko_bindings/sugar/ns_t_array.rs
index 5d9c005f0e3..6bc389702f5 100644
--- a/components/style/gecko_bindings/sugar/ns_t_array.rs
+++ b/components/style/gecko_bindings/sugar/ns_t_array.rs
@@ -93,4 +93,13 @@ impl<T> nsTArray<T> {
         let mut header = self.header_mut();
         header.mLength = len;
     }
+
+    /// Resizes an array containing only POD elements
+    ///
+    /// This will not leak since it only works on POD types (and thus doesn't assert)
+    pub unsafe fn set_len_pod(&mut self, len: u32) where T: Copy {
+        self.ensure_capacity(len as usize);
+        let mut header = unsafe { self.header_mut() };
+        header.mLength = len;
+    }
 }
diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index 70363eba25c..5d79857be93 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -328,6 +328,39 @@ def set_gecko_property(ffi_name, expr):
 % endif
 </%def>
 
+<%def name="impl_absolute_length(ident, gecko_ffi_name, need_clone=False)">
+    #[allow(non_snake_case)]
+    pub fn set_${ident}(&mut self, v: longhands::${ident}::computed_value::T) {
+        ${set_gecko_property(gecko_ffi_name, "v.0")}
+    }
+    <%call expr="impl_simple_copy(ident, gecko_ffi_name)"></%call>
+    % if need_clone:
+        #[allow(non_snake_case)]
+        pub fn clone_${ident}(&self) -> longhands::${ident}::computed_value::T {
+            Au(self.gecko.${gecko_ffi_name})
+        }
+    % endif
+</%def>
+
+<%def name="impl_position(ident, gecko_ffi_name, need_clone=False)">
+    #[allow(non_snake_case)]
+    pub fn set_${ident}(&mut self, v: longhands::${ident}::computed_value::T) {
+        ${set_gecko_property("%s.mXPosition" % gecko_ffi_name, "v.horizontal.into()")}
+        ${set_gecko_property("%s.mYPosition" % gecko_ffi_name, "v.vertical.into()")}
+    }
+    <%call expr="impl_simple_copy(ident, gecko_ffi_name)"></%call>
+    % if need_clone:
+        #[allow(non_snake_case)]
+        pub fn clone_${ident}(&self) -> longhands::${ident}::computed_value::T {
+            use values::computed::Position;
+            Position {
+                horizontal: self.gecko.${gecko_ffi_name}.mXPosition.into(),
+                vertical: self.gecko.${gecko_ffi_name}.mYPosition.into(),
+            }
+        }
+    % endif
+</%def>
+
 <%def name="impl_color(ident, gecko_ffi_name, need_clone=False, complex_color=True)">
 <%call expr="impl_color_setter(ident, gecko_ffi_name, complex_color)"></%call>
 <%call expr="impl_color_copy(ident, gecko_ffi_name, complex_color)"></%call>
@@ -501,7 +534,8 @@ impl Debug for ${style_struct.gecko_struct_name} {
     # Types used with predefined_type()-defined properties that we can auto-generate.
     predefined_types = {
         "length::LengthOrAuto": impl_style_coord,
-        "Length": impl_style_coord,
+        "Length": impl_absolute_length,
+        "Position": impl_position,
         "LengthOrPercentage": impl_style_coord,
         "LengthOrPercentageOrAuto": impl_style_coord,
         "LengthOrPercentageOrNone": impl_style_coord,
@@ -1169,7 +1203,8 @@ fn static_assert() {
                           animation-iteration-count animation-timing-function
                           -moz-binding page-break-before page-break-after
                           scroll-snap-points-x scroll-snap-points-y transform
-                          scroll-snap-type-y perspective-origin transform-origin""" %>
+                          scroll-snap-type-y scroll-snap-coordinate
+                          perspective-origin transform-origin""" %>
 <%self:impl_trait style_struct_name="Box" skip_longhands="${skip_box_longhands}">
 
     // We manually-implement the |display| property until we get general
@@ -1340,6 +1375,34 @@ fn static_assert() {
 
     ${impl_coord_copy('scroll_snap_points_y', 'mScrollSnapPointsY')}
 
+    pub fn set_scroll_snap_coordinate(&mut self, v: longhands::scroll_snap_coordinate::computed_value::T) {
+        unsafe { self.gecko.mScrollSnapCoordinate.set_len_pod(v.0.len() as u32); }
+        for (gecko, servo) in self.gecko.mScrollSnapCoordinate
+                               .iter_mut()
+                               .zip(v.0.iter()) {
+            gecko.mXPosition = servo.horizontal.into();
+            gecko.mYPosition = servo.vertical.into();
+        }
+    }
+
+    pub fn copy_scroll_snap_coordinate_from(&mut self, other: &Self) {
+        unsafe {
+            self.gecko.mScrollSnapCoordinate
+                .set_len_pod(other.gecko.mScrollSnapCoordinate.len() as u32);
+        }
+
+        for (this, that) in self.gecko.mScrollSnapCoordinate
+                               .iter_mut()
+                               .zip(other.gecko.mScrollSnapCoordinate.iter()) {
+            *this = *that;
+        }
+    }
+
+    pub fn clone_scroll_snap_coordinate(&self) -> longhands::scroll_snap_coordinate::computed_value::T {
+        let vec = self.gecko.mScrollSnapCoordinate.iter().map(|f| f.into()).collect();
+        longhands::scroll_snap_coordinate::computed_value::T(vec)
+    }
+
     <%def name="transform_function_arm(name, keyword, items)">
         <%
             pattern = None
@@ -1971,7 +2034,7 @@ fn static_assert() {
 </%self:impl_trait>
 
 <%self:impl_trait style_struct_name="List"
-                  skip_longhands="list-style-image list-style-type quotes"
+                  skip_longhands="list-style-image list-style-type quotes -moz-image-region"
                   skip_additionals="*">
 
     pub fn set_list_style_image(&mut self, image: longhands::list_style_image::computed_value::T) {
@@ -2037,6 +2100,28 @@ fn static_assert() {
         unsafe { self.gecko.mQuotes.set(&other.gecko.mQuotes); }
     }
 
+    #[allow(non_snake_case)]
+    pub fn set__moz_image_region(&mut self, v: longhands::_moz_image_region::computed_value::T) {
+        use values::Either;
+
+        match v {
+            Either::Second(_auto) => {
+                self.gecko.mImageRegion.x = 0;
+                self.gecko.mImageRegion.y = 0;
+                self.gecko.mImageRegion.width = 0;
+                self.gecko.mImageRegion.height = 0;
+            }
+            Either::First(rect) => {
+                self.gecko.mImageRegion.x = rect.left.0;
+                self.gecko.mImageRegion.y = rect.top.0;
+                self.gecko.mImageRegion.height = rect.bottom.unwrap_or(Au(0)).0 - self.gecko.mImageRegion.y;
+                self.gecko.mImageRegion.width = rect.right.unwrap_or(Au(0)).0 - self.gecko.mImageRegion.x;
+            }
+        }
+    }
+
+    ${impl_simple_copy('_moz_image_region', 'mImageRegion')}
+
 </%self:impl_trait>
 
 <%self:impl_trait style_struct_name="Effects"
@@ -2204,7 +2289,7 @@ fn static_assert() {
 
 <%self:impl_trait style_struct_name="InheritedText"
                   skip_longhands="text-align text-emphasis-style text-shadow line-height letter-spacing word-spacing
-                                  -webkit-text-stroke-width">
+                                  -webkit-text-stroke-width text-emphasis-position -moz-tab-size">
 
     <% text_align_keyword = Keyword("text-align", "start end left right center justify -moz-center -moz-left " +
                                                   "-moz-right match-parent") %>
@@ -2310,6 +2395,26 @@ fn static_assert() {
         }
     }
 
+    pub fn set_text_emphasis_position(&mut self, v: longhands::text_emphasis_position::computed_value::T) {
+        use properties::longhands::text_emphasis_position::*;
+
+        let mut result = match v.0 {
+            HorizontalWritingModeValue::Over => structs::NS_STYLE_TEXT_EMPHASIS_POSITION_OVER as u8,
+            HorizontalWritingModeValue::Under => structs::NS_STYLE_TEXT_EMPHASIS_POSITION_UNDER as u8,
+        };
+        match v.1 {
+            VerticalWritingModeValue::Right => {
+                result |= structs::NS_STYLE_TEXT_EMPHASIS_POSITION_RIGHT as u8;
+            }
+            VerticalWritingModeValue::Left => {
+                result |= structs::NS_STYLE_TEXT_EMPHASIS_POSITION_LEFT as u8;
+            }
+        }
+        self.gecko.mTextEmphasisPosition = result;
+    }
+
+    <%call expr="impl_simple_copy('text_emphasis_position', 'mTextEmphasisPosition')"></%call>
+
     pub fn set_text_emphasis_style(&mut self, v: longhands::text_emphasis_style::computed_value::T) {
         use nsstring::nsCString;
         use properties::longhands::text_emphasis_style::computed_value::T;
@@ -2353,6 +2458,22 @@ fn static_assert() {
 
     <%call expr="impl_app_units('_webkit_text_stroke_width', 'mWebkitTextStrokeWidth', need_clone=False)"></%call>
 
+    #[allow(non_snake_case)]
+    pub fn set__moz_tab_size(&mut self, v: longhands::_moz_tab_size::computed_value::T) {
+        use values::Either;
+
+        match v {
+            Either::Second(number) => {
+                self.gecko.mTabSize.set_value(CoordDataValue::Factor(number));
+            }
+            Either::First(au) => {
+                self.gecko.mTabSize.set(au);
+            }
+        }
+    }
+
+    <%call expr="impl_coord_copy('_moz_tab_size', 'mTabSize')"></%call>
+
 </%self:impl_trait>
 
 <%self:impl_trait style_struct_name="Text"
@@ -2815,6 +2936,18 @@ clip-path
     }
 </%self:impl_trait>
 
+<%self:impl_trait style_struct_name="XUL"
+                  skip_longhands="-moz-stack-sizing">
+
+    #[allow(non_snake_case)]
+    pub fn set__moz_stack_sizing(&mut self, v: longhands::_moz_stack_sizing::computed_value::T) {
+        use properties::longhands::_moz_stack_sizing::computed_value::T;
+        self.gecko.mStretchStack = v == T::stretch_to_fit;
+    }
+
+    ${impl_simple_copy('_moz_stack_sizing', 'mStretchStack')}
+</%self:impl_trait>
+
 <%def name="define_ffi_struct_accessor(style_struct)">
 #[no_mangle]
 #[allow(non_snake_case, unused_variables)]
diff --git a/components/style/properties/helpers.mako.rs b/components/style/properties/helpers.mako.rs
index 30c6873a8a2..3d84c4a8190 100644
--- a/components/style/properties/helpers.mako.rs
+++ b/components/style/properties/helpers.mako.rs
@@ -21,8 +21,9 @@
     </%call>
 </%def>
 
-<%def name="predefined_type(name, type, initial_value, parse_method='parse', needs_context=True, **kwargs)">
-    <%call expr="longhand(name, predefined_type=type, **kwargs)">
+<%def name="predefined_type(name, type, initial_value, parse_method='parse',
+            needs_context=True, vector=False, **kwargs)">
+    <%def name="predefined_type_inner(name, type, initial_value, parse_method)">
         #[allow(unused_imports)]
         use app_units::Au;
         use cssparser::{Color as CSSParserColor, RGBA};
@@ -40,7 +41,16 @@
             specified::${type}::${parse_method}(input)
             % endif
         }
-    </%call>
+    </%def>
+    % if vector:
+        <%call expr="vector_longhand(name, predefined_type=type, **kwargs)">
+            ${predefined_type_inner(name, type, initial_value, parse_method)}
+        </%call>
+    % else:
+        <%call expr="longhand(name, predefined_type=type, **kwargs)">
+            ${predefined_type_inner(name, type, initial_value, parse_method)}
+        </%call>
+    % endif
 </%def>
 
 // FIXME (Manishearth): Add computed_value_as_specified argument
@@ -56,7 +66,7 @@
     We assume that the default/initial value is an empty vector for these.
     `initial_value` need not be defined for these.
 </%doc>
-<%def name="vector_longhand(name, gecko_only=False, allow_empty=False, **kwargs)">
+<%def name="vector_longhand(name, gecko_only=False, allow_empty=False, delegate_animate=False, **kwargs)">
     <%call expr="longhand(name, **kwargs)">
         % if not gecko_only:
             use std::fmt;
@@ -87,6 +97,15 @@
                 #[derive(Debug, Clone, PartialEq)]
                 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
                 pub struct T(pub Vec<single_value::T>);
+
+                % if delegate_animate:
+                    use properties::animated_properties::Interpolate;
+                    impl Interpolate for T {
+                        fn interpolate(&self, other: &Self, progress: f64) -> Result<Self, ()> {
+                            self.0.interpolate(&other.0, progress).map(T)
+                        }
+                    }
+                % endif
             }
 
             impl ToCss for computed_value::T {
diff --git a/components/style/properties/helpers/animated_properties.mako.rs b/components/style/properties/helpers/animated_properties.mako.rs
index 35fb529c851..fae2c82e54d 100644
--- a/components/style/properties/helpers/animated_properties.mako.rs
+++ b/components/style/properties/helpers/animated_properties.mako.rs
@@ -10,8 +10,6 @@ use euclid::{Point2D, Size2D};
 #[cfg(feature = "gecko")] use gecko_bindings::structs::nsCSSPropertyID;
 use properties::{DeclaredValue, PropertyDeclaration};
 use properties::longhands;
-use properties::longhands::background_position_x::computed_value::T as BackgroundPositionX;
-use properties::longhands::background_position_y::computed_value::T as BackgroundPositionY;
 use properties::longhands::background_size::computed_value::T as BackgroundSize;
 use properties::longhands::font_weight::computed_value::T as FontWeight;
 use properties::longhands::line_height::computed_value::T as LineHeight;
@@ -33,7 +31,7 @@ use super::ComputedValues;
 use values::CSSFloat;
 use values::Either;
 use values::computed::{Angle, LengthOrPercentageOrAuto, LengthOrPercentageOrNone};
-use values::computed::{BorderRadiusSize, LengthOrNone};
+use values::computed::{BorderRadiusSize, ClipRect, LengthOrNone};
 use values::computed::{CalcLengthOrPercentage, Context, LengthOrPercentage};
 use values::computed::position::{HorizontalPosition, Position, VerticalPosition};
 use values::computed::ToComputedValue;
@@ -724,17 +722,16 @@ impl Interpolate for VerticalPosition {
 
 impl RepeatableListInterpolate for VerticalPosition {}
 
-impl Interpolate for BackgroundPositionX {
+/// https://drafts.csswg.org/css-transitions/#animtype-rect
+impl Interpolate for ClipRect {
     #[inline]
-    fn interpolate(&self, other: &Self, progress: f64) -> Result<Self, ()> {
-        Ok(BackgroundPositionX(try!(self.0.interpolate(&other.0, progress))))
-    }
-}
-
-impl Interpolate for BackgroundPositionY {
-    #[inline]
-    fn interpolate(&self, other: &Self, progress: f64) -> Result<Self, ()> {
-        Ok(BackgroundPositionY(try!(self.0.interpolate(&other.0, progress))))
+    fn interpolate(&self, other: &Self, time: f64) -> Result<Self, ()> {
+        Ok(ClipRect {
+            top: try!(self.top.interpolate(&other.top, time)),
+            right: try!(self.right.interpolate(&other.right, time)),
+            bottom: try!(self.bottom.interpolate(&other.bottom, time)),
+            left: try!(self.left.interpolate(&other.left, time)),
+        })
     }
 }
 
diff --git a/components/style/properties/longhand/background.mako.rs b/components/style/properties/longhand/background.mako.rs
index b4b0686e542..f8622e75d29 100644
--- a/components/style/properties/longhand/background.mako.rs
+++ b/components/style/properties/longhand/background.mako.rs
@@ -89,7 +89,8 @@ ${helpers.predefined_type("background-color", "CSSColor",
 </%helpers:vector_longhand>
 
 <%helpers:vector_longhand name="background-position-x" animatable="True"
-                          spec="https://drafts.csswg.org/css-backgrounds-4/#propdef-background-position-x">
+                          spec="https://drafts.csswg.org/css-backgrounds-4/#propdef-background-position-x"
+                          delegate_animate="True">
     use std::fmt;
     use style_traits::ToCss;
     use values::HasViewportPercentage;
@@ -139,7 +140,8 @@ ${helpers.predefined_type("background-color", "CSSColor",
 </%helpers:vector_longhand>
 
 <%helpers:vector_longhand name="background-position-y" animatable="True"
-                          spec="https://drafts.csswg.org/css-backgrounds-4/#propdef-background-position-y">
+                          spec="https://drafts.csswg.org/css-backgrounds-4/#propdef-background-position-y"
+                          delegate_animate="True">
     use std::fmt;
     use style_traits::ToCss;
     use values::HasViewportPercentage;
diff --git a/components/style/properties/longhand/border.mako.rs b/components/style/properties/longhand/border.mako.rs
index 624e8ac7926..8a85377febb 100644
--- a/components/style/properties/longhand/border.mako.rs
+++ b/components/style/properties/longhand/border.mako.rs
@@ -257,10 +257,10 @@ ${helpers.single_keyword("-moz-float-edge", "content-box margin-box",
         }
     }
 
-    pub fn parse(_context: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue, ()> {
+    pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue, ()> {
         let mut values = vec![];
         for _ in 0..4 {
-            let value = input.try(|input| LengthOrNumber::parse_non_negative(input));
+            let value = input.try(|input| LengthOrNumber::parse_non_negative(context, input));
             match value {
                 Ok(val) => values.push(val),
                 Err(_) => break,
diff --git a/components/style/properties/longhand/box.mako.rs b/components/style/properties/longhand/box.mako.rs
index 95d23dbf0e4..9fbe615fea0 100644
--- a/components/style/properties/longhand/box.mako.rs
+++ b/components/style/properties/longhand/box.mako.rs
@@ -1049,6 +1049,25 @@ ${helpers.single_keyword("animation-fill-mode",
 </%helpers:longhand>
 
 
+${helpers.predefined_type("scroll-snap-destination",
+                          "Position",
+                          "computed::Position::zero()",
+                          products="gecko",
+                          boxed="True",
+                          spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/scroll-snap-destination)",
+                          animatable=True)}
+
+${helpers.predefined_type("scroll-snap-coordinate",
+                          "Position",
+                          "computed::Position::zero()",
+                          vector=True,
+                          products="gecko",
+                          spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/scroll-snap-destination)",
+                          animatable=True,
+                          allow_empty=True,
+                          delegate_animate=True)}
+
+
 
 <%helpers:longhand name="transform" products="gecko servo" extra_prefixes="webkit"
                    animatable="True"
diff --git a/components/style/properties/longhand/effects.mako.rs b/components/style/properties/longhand/effects.mako.rs
index b01874e8095..eb4879f7afb 100644
--- a/components/style/properties/longhand/effects.mako.rs
+++ b/components/style/properties/longhand/effects.mako.rs
@@ -77,217 +77,13 @@ ${helpers.predefined_type("opacity",
 </%helpers:vector_longhand>
 
 // FIXME: This prop should be animatable
-<%helpers:longhand name="clip" products="servo" animatable="False" boxed="True"
-                   spec="https://drafts.fxtf.org/css-masking/#clip-property">
-    use std::fmt;
-    use style_traits::ToCss;
-    use values::HasViewportPercentage;
-
-    // NB: `top` and `left` are 0 if `auto` per CSS 2.1 11.1.2.
-
-    pub mod computed_value {
-        use app_units::Au;
-        use properties::animated_properties::Interpolate;
-
-        #[derive(Clone, PartialEq, Eq, Copy, Debug)]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        pub struct ClipRect {
-            pub top: Au,
-            pub right: Option<Au>,
-            pub bottom: Option<Au>,
-            pub left: Au,
-        }
-
-        #[derive(Debug, Clone, PartialEq)]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        pub struct T(pub Option<ClipRect>);
-
-
-        /// https://drafts.csswg.org/css-transitions/#animtype-rect
-        impl Interpolate for ClipRect {
-            #[inline]
-            fn interpolate(&self, other: &Self, time: f64) -> Result<Self, ()> {
-                Ok(ClipRect {
-                    top: try!(self.top.interpolate(&other.top, time)),
-                    right: try!(self.right.interpolate(&other.right, time)),
-                    bottom: try!(self.bottom.interpolate(&other.bottom, time)),
-                    left: try!(self.left.interpolate(&other.left, time)),
-                })
-            }
-        }
-    }
-
-    impl ToCss for computed_value::T {
-        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-            match self.0 {
-                None => dest.write_str("auto"),
-                Some(rect) => {
-                    try!(dest.write_str("rect("));
-                    try!(rect.top.to_css(dest));
-                    try!(dest.write_str(", "));
-                    if let Some(right) = rect.right {
-                        try!(right.to_css(dest));
-                        try!(dest.write_str(", "));
-                    } else {
-                        try!(dest.write_str("auto, "));
-                    }
-
-                    if let Some(bottom) = rect.bottom {
-                        try!(bottom.to_css(dest));
-                        try!(dest.write_str(", "));
-                    } else {
-                        try!(dest.write_str("auto, "));
-                    }
-
-                    try!(rect.left.to_css(dest));
-                    try!(dest.write_str(")"));
-                    Ok(())
-                }
-            }
-        }
-    }
-
-    impl HasViewportPercentage for SpecifiedClipRect {
-        fn has_viewport_percentage(&self) -> bool {
-            self.top.has_viewport_percentage() ||
-            self.right.as_ref().map_or(false, |x| x.has_viewport_percentage()) ||
-            self.bottom.as_ref().map_or(false, |x| x.has_viewport_percentage()) ||
-            self.left.has_viewport_percentage()
-        }
-    }
-
-    #[derive(Clone, Debug, PartialEq)]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-    pub struct SpecifiedClipRect {
-        pub top: specified::Length,
-        pub right: Option<specified::Length>,
-        pub bottom: Option<specified::Length>,
-        pub left: specified::Length,
-    }
-
-    impl HasViewportPercentage for SpecifiedValue {
-        fn has_viewport_percentage(&self) -> bool {
-            self.0.as_ref().map_or(false, |x| x.has_viewport_percentage())
-        }
-    }
-
-    #[derive(Clone, Debug, PartialEq)]
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-    pub struct SpecifiedValue(Option<SpecifiedClipRect>);
-
-    impl ToCss for SpecifiedClipRect {
-        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-            try!(dest.write_str("rect("));
-
-            try!(self.top.to_css(dest));
-            try!(dest.write_str(", "));
-
-            if let Some(ref right) = self.right {
-                try!(right.to_css(dest));
-                try!(dest.write_str(", "));
-            } else {
-                try!(dest.write_str("auto, "));
-            }
-
-            if let Some(ref bottom) = self.bottom {
-                try!(bottom.to_css(dest));
-                try!(dest.write_str(", "));
-            } else {
-                try!(dest.write_str("auto, "));
-            }
-
-            try!(self.left.to_css(dest));
-
-            try!(dest.write_str(")"));
-            Ok(())
-        }
-    }
-
-    impl ToCss for SpecifiedValue {
-        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-            if let Some(ref rect) = self.0 {
-                rect.to_css(dest)
-            } else {
-                dest.write_str("auto")
-            }
-        }
-    }
-
-    #[inline]
-    pub fn get_initial_value() -> computed_value::T {
-        computed_value::T(None)
-    }
-
-    impl ToComputedValue for SpecifiedValue {
-        type ComputedValue = computed_value::T;
-
-        #[inline]
-        fn to_computed_value(&self, context: &Context) -> computed_value::T {
-            computed_value::T(self.0.as_ref().map(|value| computed_value::ClipRect {
-                top: value.top.to_computed_value(context),
-                right: value.right.as_ref().map(|right| right.to_computed_value(context)),
-                bottom: value.bottom.as_ref().map(|bottom| bottom.to_computed_value(context)),
-                left: value.left.to_computed_value(context),
-            }))
-        }
-
-        #[inline]
-        fn from_computed_value(computed: &computed_value::T) -> Self {
-            SpecifiedValue(computed.0.map(|value| SpecifiedClipRect {
-                top: ToComputedValue::from_computed_value(&value.top),
-                right: value.right.map(|right| ToComputedValue::from_computed_value(&right)),
-                bottom: value.bottom.map(|bottom| ToComputedValue::from_computed_value(&bottom)),
-                left: ToComputedValue::from_computed_value(&value.left),
-            }))
-        }
-    }
-
-    pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue, ()> {
-        use app_units::Au;
-        use std::ascii::AsciiExt;
-        use values::specified::Length;
-
-        fn parse_argument(context: &ParserContext, input: &mut Parser) -> Result<Option<Length>, ()> {
-            if input.try(|input| input.expect_ident_matching("auto")).is_ok() {
-                Ok(None)
-            } else {
-                Length::parse(context, input).map(Some)
-            }
-        }
-
-        if input.try(|input| input.expect_ident_matching("auto")).is_ok() {
-            return Ok(SpecifiedValue(None))
-        }
-        if !try!(input.expect_function()).eq_ignore_ascii_case("rect") {
-            return Err(())
-        }
-
-        input.parse_nested_block(|input| {
-            let top = try!(parse_argument(context, input));
-            let right;
-            let bottom;
-            let left;
-
-            if input.try(|input| input.expect_comma()).is_ok() {
-                right = try!(parse_argument(context, input));
-                try!(input.expect_comma());
-                bottom = try!(parse_argument(context, input));
-                try!(input.expect_comma());
-                left = try!(parse_argument(context, input));
-            } else {
-                right = try!(parse_argument(context, input));
-                bottom = try!(parse_argument(context, input));
-                left = try!(parse_argument(context, input));
-            }
-            Ok(SpecifiedValue(Some(SpecifiedClipRect {
-                top: top.unwrap_or(Length::zero()),
-                right: right,
-                bottom: bottom,
-                left: left.unwrap_or(Length::zero()),
-            })))
-        })
-    }
-</%helpers:longhand>
+${helpers.predefined_type("clip",
+                          "ClipRectOrAuto",
+                          "computed::ClipRectOrAuto::auto()",
+                          animatable=False,
+                          products="servo",
+                          boxed="True",
+                          spec="https://drafts.fxtf.org/css-masking/#clip-property")}
 
 // FIXME: This prop should be animatable
 <%helpers:longhand name="filter" animatable="False" extra_prefixes="webkit"
diff --git a/components/style/properties/longhand/inherited_text.mako.rs b/components/style/properties/longhand/inherited_text.mako.rs
index 335ad1f1ca1..dc3e32f99b3 100644
--- a/components/style/properties/longhand/inherited_text.mako.rs
+++ b/components/style/properties/longhand/inherited_text.mako.rs
@@ -973,7 +973,7 @@ ${helpers.single_keyword("text-align-last",
     }
 </%helpers:longhand>
 
-<%helpers:longhand name="text-emphasis-position" animatable="False" products="none"
+<%helpers:longhand name="text-emphasis-position" animatable="False" products="gecko"
                    spec="https://drafts.csswg.org/css-text-decor/#propdef-text-emphasis-position">
     use std::fmt;
     use values::computed::ComputedValueAsSpecified;
@@ -1030,6 +1030,15 @@ ${helpers.predefined_type("text-emphasis-color", "CSSColor",
                           boxed=True,
                           spec="https://drafts.csswg.org/css-text-decor/#propdef-text-emphasis-color")}
 
+
+${helpers.predefined_type(
+    "-moz-tab-size", "LengthOrNumber",
+    "::values::Either::Second(8.0)",
+    "parse_non_negative",
+    products="gecko", animatable=False,
+    spec="https://drafts.csswg.org/css-text-3/#tab-size-property")}
+
+
 // CSS Compatibility
 // https://compat.spec.whatwg.org
 ${helpers.predefined_type(
@@ -1070,6 +1079,7 @@ ${helpers.predefined_type(
     }
 </%helpers:longhand>
 
+
 // CSS Ruby Layout Module Level 1
 // https://drafts.csswg.org/css-ruby/
 ${helpers.single_keyword("ruby-align", "start center space-between space-around",
diff --git a/components/style/properties/longhand/list.mako.rs b/components/style/properties/longhand/list.mako.rs
index f4f84f9e884..91e003d2575 100644
--- a/components/style/properties/longhand/list.mako.rs
+++ b/components/style/properties/longhand/list.mako.rs
@@ -101,3 +101,11 @@ ${helpers.predefined_type("list-style-image", "UrlOrNone", "Either::Second(None_
         }
     }
 </%helpers:longhand>
+
+${helpers.predefined_type("-moz-image-region",
+                          "ClipRectOrAuto",
+                          "computed::ClipRectOrAuto::auto()",
+                          animatable=False,
+                          products="gecko",
+                          boxed="True",
+                          spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-image-region)")}
diff --git a/components/style/properties/longhand/outline.mako.rs b/components/style/properties/longhand/outline.mako.rs
index b47f45d7a68..cd242797f0d 100644
--- a/components/style/properties/longhand/outline.mako.rs
+++ b/components/style/properties/longhand/outline.mako.rs
@@ -114,5 +114,5 @@ ${helpers.predefined_type("outline-color", "CSSColor", "::cssparser::Color::Curr
         spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-outline-radius)")}
 % endfor
 
-${helpers.predefined_type("outline-offset", "Length", "Au(0)", products="servo", animatable=True,
+${helpers.predefined_type("outline-offset", "Length", "Au(0)", products="servo gecko", animatable=True,
                           spec="https://drafts.csswg.org/css-ui/#propdef-outline-offset")}
diff --git a/components/style/properties/longhand/position.mako.rs b/components/style/properties/longhand/position.mako.rs
index 3e55cb2bd3b..9c801358988 100644
--- a/components/style/properties/longhand/position.mako.rs
+++ b/components/style/properties/longhand/position.mako.rs
@@ -210,6 +210,14 @@ ${helpers.single_keyword("object-fit", "fill contain cover none scale-down",
                          products="gecko", animatable=False,
                          spec="https://drafts.csswg.org/css-images/#propdef-object-fit")}
 
+${helpers.predefined_type("object-position",
+                          "Position",
+                          "computed::Position::zero()",
+                          products="gecko",
+                          boxed="True",
+                          spec="https://drafts.csswg.org/css-images-3/#the-object-position",
+                          animatable=True)}
+
 <% grid_longhands = ["grid-row-start", "grid-row-end", "grid-column-start", "grid-column-end"] %>
 
 % for longhand in grid_longhands:
diff --git a/components/style/properties/longhand/ui.mako.rs b/components/style/properties/longhand/ui.mako.rs
index 62948316e70..79d25467df6 100644
--- a/components/style/properties/longhand/ui.mako.rs
+++ b/components/style/properties/longhand/ui.mako.rs
@@ -23,3 +23,9 @@ ${helpers.single_keyword("-moz-user-select", "auto text none all", products="gec
                          gecko_inexhaustive=True,
                          animatable=False,
                          spec="https://drafts.csswg.org/css-ui-4/#propdef-user-select")}
+
+${helpers.single_keyword("-moz-window-dragging", "default drag no-drag", products="gecko",
+                         gecko_ffi_name="mWindowDragging",
+                         gecko_enum_prefix="StyleWindowDragging",
+                         animatable=False,
+                         spec="None (Nonstandard Firefox-only property)")}
diff --git a/components/style/properties/longhand/xul.mako.rs b/components/style/properties/longhand/xul.mako.rs
index 7862b1d9177..6cf61f3948a 100644
--- a/components/style/properties/longhand/xul.mako.rs
+++ b/components/style/properties/longhand/xul.mako.rs
@@ -22,3 +22,10 @@ ${helpers.predefined_type("-moz-box-flex", "Number", "0.0", "parse_non_negative"
                           animatable=False,
                           alias="-webkit-box-flex",
                           spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/box-flex)")}
+
+
+${helpers.single_keyword("-moz-stack-sizing", "stretch-to-fit ignore",
+                         products="gecko", gecko_ffi_name="mStretchStack",
+                         gecko_constant_prefix="NS_STYLE_STACK_SIZING",
+                         animatable=False,
+                         spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-stack-sizing)")}
diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index 3f014d3368f..02cbcbf1150 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -1589,7 +1589,7 @@ impl ComputedValues {
         // TODO(gw): Add clip-path, isolation, mask-image, mask-border-source when supported.
         if effects.opacity < 1.0 ||
            !effects.filter.is_empty() ||
-           effects.clip.0.is_some() {
+           !effects.clip.is_auto() {
            effects.mix_blend_mode != mix_blend_mode::T::normal ||
             return transform_style::T::flat;
         }
@@ -2290,10 +2290,10 @@ pub fn modify_style_for_text(style: &mut Arc<ComputedValues>) {
 /// doesn't clip its children.
 #[cfg(feature = "servo")]
 pub fn modify_style_for_inline_absolute_hypothetical_fragment(style: &mut Arc<ComputedValues>) {
-    if style.get_effects().clip.0.is_some() {
+    if !style.get_effects().clip.is_auto() {
         let mut style = Arc::make_mut(style);
         let effects_style = Arc::make_mut(&mut style.effects);
-        effects_style.clip.0 = None
+        effects_style.clip = Either::auto()
     }
 }
 
diff --git a/components/style/values/computed/mod.rs b/components/style/values/computed/mod.rs
index a653d18918c..36b3b2dc6ac 100644
--- a/components/style/values/computed/mod.rs
+++ b/components/style/values/computed/mod.rs
@@ -15,11 +15,12 @@ use super::{CSSFloat, specified};
 pub use cssparser::Color as CSSColor;
 pub use self::image::{AngleOrCorner, EndingShape as GradientShape, Gradient, GradientKind, Image};
 pub use self::image::{LengthOrKeyword, LengthOrPercentageOrKeyword};
-pub use super::{Either, None_};
+pub use super::{Auto, Either, None_};
 pub use super::specified::{Angle, BorderStyle, GridLine, Time, UrlOrNone};
 pub use super::specified::url::UrlExtraData;
 pub use self::length::{CalcLengthOrPercentage, Length, LengthOrNumber, LengthOrPercentage, LengthOrPercentageOrAuto};
 pub use self::length::{LengthOrPercentageOrAutoOrContent, LengthOrPercentageOrNone, LengthOrNone};
+pub use self::position::Position;
 
 pub mod basic_shape;
 pub mod image;
@@ -176,3 +177,57 @@ pub type Number = CSSFloat;
 
 /// A type used for opacity.
 pub type Opacity = CSSFloat;
+
+
+#[derive(Clone, PartialEq, Eq, Copy, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[allow(missing_docs)]
+/// A computed cliprect for clip and image-region
+pub struct ClipRect {
+    pub top: Au,
+    pub right: Option<Au>,
+    pub bottom: Option<Au>,
+    pub left: Au,
+}
+
+impl ToCss for ClipRect {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        try!(dest.write_str("rect("));
+        try!(self.top.to_css(dest));
+        try!(dest.write_str(", "));
+        if let Some(right) = self.right {
+            try!(right.to_css(dest));
+            try!(dest.write_str(", "));
+        } else {
+            try!(dest.write_str("auto, "));
+        }
+
+        if let Some(bottom) = self.bottom {
+            try!(bottom.to_css(dest));
+            try!(dest.write_str(", "));
+        } else {
+            try!(dest.write_str("auto, "));
+        }
+
+        try!(self.left.to_css(dest));
+        dest.write_str(")")
+    }
+}
+
+/// rect(...) | auto
+pub type ClipRectOrAuto = Either<ClipRect, Auto>;
+
+impl ClipRectOrAuto {
+    /// Return an auto (default for clip-rect and image-region) value
+    pub fn auto() -> Self {
+        Either::Second(Auto)
+    }
+
+    /// Check if it is auto
+    pub fn is_auto(&self) -> bool {
+        match *self {
+            Either::Second(_) => true,
+            _ => false
+        }
+    }
+}
diff --git a/components/style/values/computed/position.rs b/components/style/values/computed/position.rs
index a9b51953810..d2cc4b1e48f 100644
--- a/components/style/values/computed/position.rs
+++ b/components/style/values/computed/position.rs
@@ -19,6 +19,16 @@ pub struct Position {
     pub vertical: LengthOrPercentage,
 }
 
+impl Position {
+    /// Construct a position at (0, 0)
+    pub fn zero() -> Self {
+        Position {
+            horizontal: LengthOrPercentage::zero(),
+            vertical: LengthOrPercentage::zero(),
+        }
+    }
+}
+
 impl ToCss for Position {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         try!(self.horizontal.to_css(dest));
diff --git a/components/style/values/specified/length.rs b/components/style/values/specified/length.rs
index 99c4a09abf1..fb4ac9c0b60 100644
--- a/components/style/values/specified/length.rs
+++ b/components/style/values/specified/length.rs
@@ -1215,7 +1215,7 @@ pub type LengthOrNumber = Either<Length, Number>;
 
 impl LengthOrNumber {
     /// Parse a non-negative LengthOrNumber.
-    pub fn parse_non_negative(input: &mut Parser) -> Result<Self, ()> {
+    pub fn parse_non_negative(_context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
         // We try to parse as a Number first because, for cases like LengthOrNumber,
         // we want "0" to be parsed as a plain Number rather than a Length (0px); this
         // matches the behaviour of all major browsers
diff --git a/components/style/values/specified/mod.rs b/components/style/values/specified/mod.rs
index dac10f661f7..8e3315f0ea6 100644
--- a/components/style/values/specified/mod.rs
+++ b/components/style/values/specified/mod.rs
@@ -16,7 +16,7 @@ use std::f32::consts::PI;
 use std::fmt;
 use std::ops::Mul;
 use style_traits::ToCss;
-use super::{CSSFloat, HasViewportPercentage, Either, None_};
+use super::{Auto, CSSFloat, HasViewportPercentage, Either, None_};
 use super::computed::{ComputedValueAsSpecified, Context, ToComputedValue};
 use super::computed::Shadow as ComputedShadow;
 
@@ -27,6 +27,7 @@ pub use self::image::{SizeKeyword, VerticalDirection};
 pub use self::length::{FontRelativeLength, ViewportPercentageLength, CharacterWidth, Length, CalcLengthOrPercentage};
 pub use self::length::{Percentage, LengthOrNone, LengthOrNumber, LengthOrPercentage, LengthOrPercentageOrAuto};
 pub use self::length::{LengthOrPercentageOrNone, LengthOrPercentageOrAutoOrContent, NoCalcLength, CalcUnit};
+pub use self::position::{HorizontalPosition, Position, VerticalPosition};
 
 pub mod basic_shape;
 pub mod grid;
@@ -664,3 +665,127 @@ impl Shadow {
         })
     }
 }
+
+
+impl HasViewportPercentage for ClipRect {
+    fn has_viewport_percentage(&self) -> bool {
+        self.top.has_viewport_percentage() ||
+        self.right.as_ref().map_or(false, |x| x.has_viewport_percentage()) ||
+        self.bottom.as_ref().map_or(false, |x| x.has_viewport_percentage()) ||
+        self.left.has_viewport_percentage()
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+/// rect(<top>, <left>, <bottom>, <right>) used by clip and image-region
+pub struct ClipRect {
+    /// <top> (<length> | <auto>). Auto maps to 0
+    pub top: Length,
+    /// <right> (<length> | <auto>)
+    pub right: Option<Length>,
+    /// <bottom> (<length> | <auto>)
+    pub bottom: Option<Length>,
+    /// <left> (<length> | <auto>). Auto maps to 0
+    pub left: Length,
+}
+
+
+impl ToCss for ClipRect {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        try!(dest.write_str("rect("));
+
+        try!(self.top.to_css(dest));
+        try!(dest.write_str(", "));
+
+        if let Some(ref right) = self.right {
+            try!(right.to_css(dest));
+            try!(dest.write_str(", "));
+        } else {
+            try!(dest.write_str("auto, "));
+        }
+
+        if let Some(ref bottom) = self.bottom {
+            try!(bottom.to_css(dest));
+            try!(dest.write_str(", "));
+        } else {
+            try!(dest.write_str("auto, "));
+        }
+
+        try!(self.left.to_css(dest));
+
+        try!(dest.write_str(")"));
+        Ok(())
+    }
+}
+
+impl ToComputedValue for ClipRect {
+    type ComputedValue = super::computed::ClipRect;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> super::computed::ClipRect {
+        super::computed::ClipRect {
+            top: self.top.to_computed_value(context),
+            right: self.right.as_ref().map(|right| right.to_computed_value(context)),
+            bottom: self.bottom.as_ref().map(|bottom| bottom.to_computed_value(context)),
+            left: self.left.to_computed_value(context),
+        }
+    }
+
+    #[inline]
+    fn from_computed_value(computed: &super::computed::ClipRect) -> Self {
+        ClipRect {
+            top: ToComputedValue::from_computed_value(&computed.top),
+            right: computed.right.map(|right| ToComputedValue::from_computed_value(&right)),
+            bottom: computed.bottom.map(|bottom| ToComputedValue::from_computed_value(&bottom)),
+            left: ToComputedValue::from_computed_value(&computed.left),
+        }
+    }
+}
+
+impl Parse for ClipRect {
+    fn parse(context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
+        use values::specified::Length;
+
+        fn parse_argument(context: &ParserContext, input: &mut Parser) -> Result<Option<Length>, ()> {
+            if input.try(|input| input.expect_ident_matching("auto")).is_ok() {
+                Ok(None)
+            } else {
+                Length::parse(context, input).map(Some)
+            }
+        }
+
+        if !try!(input.expect_function()).eq_ignore_ascii_case("rect") {
+            return Err(())
+        }
+
+        // NB: `top` and `left` are 0 if `auto` per CSS 2.1 11.1.2.
+        input.parse_nested_block(|input| {
+            let top = try!(parse_argument(context, input));
+            let right;
+            let bottom;
+            let left;
+
+            if input.try(|input| input.expect_comma()).is_ok() {
+                right = try!(parse_argument(context, input));
+                try!(input.expect_comma());
+                bottom = try!(parse_argument(context, input));
+                try!(input.expect_comma());
+                left = try!(parse_argument(context, input));
+            } else {
+                right = try!(parse_argument(context, input));
+                bottom = try!(parse_argument(context, input));
+                left = try!(parse_argument(context, input));
+            }
+            Ok(ClipRect {
+                top: top.unwrap_or(Length::zero()),
+                right: right,
+                bottom: bottom,
+                left: left.unwrap_or(Length::zero()),
+            })
+        })
+    }
+}
+
+/// rect(...) | auto
+pub type ClipRectOrAuto = Either<ClipRect, Auto>;