layout: Fix a couple of issues relating to intrinsic widths of inline

blocks.

* Stop double-counting border and padding for inline-block fragments.
  (Test case: `inline_block_border_intrinsic_size_a.html`.)

* Take clearance into account when determining intrinsic widths of
  blocks containing floats.

Improves the Amazon headers.

3 files changed, 19 insertions, 8 deletions

diff --git a/components/layout/block.rs b/components/layout/block.rs
index e61ad3104c8..b01a31804b2 100644
--- a/components/layout/block.rs
+++ b/components/layout/block.rs
@@ -1465,8 +1465,8 @@ impl Flow for BlockFlow {
 
         // Find the maximum inline-size from children.
         let mut computation = self.fragment.compute_intrinsic_inline_sizes();
-        let mut left_float_width = Au(0);
-        let mut right_float_width = Au(0);
+        let (mut left_float_width, mut right_float_width) = (Au(0), Au(0));
+        let (mut left_float_width_accumulator, mut right_float_width_accumulator) = (Au(0), Au(0));
         for kid in self.base.child_iter() {
             let is_absolutely_positioned =
                 flow::base(kid).flags.contains(IS_ABSOLUTELY_POSITIONED);
@@ -1477,6 +1477,15 @@ impl Flow for BlockFlow {
                     max(computation.content_intrinsic_sizes.minimum_inline_size,
                         child_base.intrinsic_inline_sizes.minimum_inline_size);
 
+                if child_base.flags.contains(CLEARS_LEFT) {
+                    left_float_width = Au::max(left_float_width, left_float_width_accumulator);
+                    left_float_width_accumulator = Au(0)
+                }
+                if child_base.flags.contains(CLEARS_RIGHT) {
+                    right_float_width = Au::max(right_float_width, right_float_width_accumulator);
+                    right_float_width_accumulator = Au(0)
+                }
+
                 match float_kind {
                     float::T::none => {
                         computation.content_intrinsic_sizes.preferred_inline_size =
@@ -1484,11 +1493,11 @@ impl Flow for BlockFlow {
                                 child_base.intrinsic_inline_sizes.preferred_inline_size);
                     }
                     float::T::left => {
-                        left_float_width = left_float_width +
+                        left_float_width_accumulator = left_float_width_accumulator +
                             child_base.intrinsic_inline_sizes.preferred_inline_size;
                     }
                     float::T::right => {
-                        right_float_width = right_float_width +
+                        right_float_width_accumulator = right_float_width_accumulator +
                             child_base.intrinsic_inline_sizes.preferred_inline_size;
                     }
                 }
@@ -1500,6 +1509,8 @@ impl Flow for BlockFlow {
         // FIXME(pcwalton): This should consider all float descendants, not just children.
         // FIXME(pcwalton): This is not well-spec'd; INTRINSIC specifies to do this, but CSS-SIZING
         // says not to. In practice, Gecko and WebKit both do this.
+        left_float_width = Au::max(left_float_width, left_float_width_accumulator);
+        right_float_width = Au::max(right_float_width, right_float_width_accumulator);
         computation.content_intrinsic_sizes.preferred_inline_size =
             max(computation.content_intrinsic_sizes.preferred_inline_size,
                 left_float_width + right_float_width);
diff --git a/components/layout/construct.rs b/components/layout/construct.rs
index c72de1d122a..c0480e8562c 100644
--- a/components/layout/construct.rs
+++ b/components/layout/construct.rs
@@ -822,7 +822,7 @@ impl<'a> FlowConstructor<'a> {
                 block_flow));
         let fragment = Fragment::new(node, fragment_info);
 
-        let mut fragment_accumulator = InlineFragmentsAccumulator::from_inline_node(node);
+        let mut fragment_accumulator = InlineFragmentsAccumulator::new();
         fragment_accumulator.fragments.push_back(fragment);
 
         let construction_item =
diff --git a/components/layout/fragment.rs b/components/layout/fragment.rs
index 8b60b4cfc72..7ad0e8895ad 100644
--- a/components/layout/fragment.rs
+++ b/components/layout/fragment.rs
@@ -882,8 +882,7 @@ impl Fragment {
             SpecificFragmentInfo::Generic |
             SpecificFragmentInfo::GeneratedContent(_) |
             SpecificFragmentInfo::Iframe(_) |
-            SpecificFragmentInfo::Image(_) |
-            SpecificFragmentInfo::InlineBlock(_) => {
+            SpecificFragmentInfo::Image(_) => {
                 QuantitiesIncludedInIntrinsicInlineSizes::all()
             }
             SpecificFragmentInfo::Table | SpecificFragmentInfo::TableCell => {
@@ -918,7 +917,8 @@ impl Fragment {
             SpecificFragmentInfo::ScannedText(_) |
             SpecificFragmentInfo::TableColumn(_) |
             SpecificFragmentInfo::UnscannedText(_) |
-            SpecificFragmentInfo::InlineAbsoluteHypothetical(_) => {
+            SpecificFragmentInfo::InlineAbsoluteHypothetical(_) |
+            SpecificFragmentInfo::InlineBlock(_) => {
                 QuantitiesIncludedInIntrinsicInlineSizes::empty()
             }
         }