From d5ca1a18dc110d2c6fbad69a517c5bca858c32be Mon Sep 17 00:00:00 2001
From: Patrick Walton <pcwalton@mimiga.net>
Date: Fri, 8 May 2015 16:33:30 -0700
Subject: [PATCH] layout: Support percentage widths in inline-blocks.

Improves Twitter.
---
 components/layout/block.rs                      |  6 +++---
 components/layout/fragment.rs                   | 13 +++++++++++++
 components/layout/inline.rs                     |  3 ++-
 tests/ref/basic.list                            |  1 +
 tests/ref/percentage_width_inline_block_a.html  | 17 +++++++++++++++++
 .../ref/percentage_width_inline_block_ref.html  | 16 ++++++++++++++++
 6 files changed, 52 insertions(+), 4 deletions(-)
 create mode 100644 tests/ref/percentage_width_inline_block_a.html
 create mode 100644 tests/ref/percentage_width_inline_block_ref.html

diff --git a/components/layout/block.rs b/components/layout/block.rs
index fa3a13c58e7..c77c9266345 100644
--- a/components/layout/block.rs
+++ b/components/layout/block.rs
@@ -2134,9 +2134,9 @@ pub trait ISizeAndMarginsComputer {
     }
 
     fn containing_block_inline_size(&self,
-                              _: &mut BlockFlow,
-                              parent_flow_inline_size: Au,
-                              _: &LayoutContext)
+                                    _: &mut BlockFlow,
+                                    parent_flow_inline_size: Au,
+                                    _: &LayoutContext)
                               -> Au {
         parent_flow_inline_size
     }
diff --git a/components/layout/fragment.rs b/components/layout/fragment.rs
index b5c96816933..c8d496c04bf 100644
--- a/components/layout/fragment.rs
+++ b/components/layout/fragment.rs
@@ -1897,6 +1897,19 @@ impl Fragment {
         }
     }
 
+    /// Determines the inline sizes of inline-block fragments. These cannot be fully computed until
+    /// inline size assignment has run for the child flow: thus it is computed "late", during
+    /// block size assignment.
+    pub fn update_late_computed_replaced_inline_size_if_necessary(&mut self) {
+        if let SpecificFragmentInfo::InlineBlock(ref mut inline_block_info) = self.specific {
+            let block_flow = inline_block_info.flow_ref.as_block();
+            let margin = block_flow.fragment.style.logical_margin();
+            self.border_box.size.inline = block_flow.fragment.border_box.size.inline +
+                MaybeAuto::from_style(margin.inline_start, Au(0)).specified_or_zero() +
+                MaybeAuto::from_style(margin.inline_end, Au(0)).specified_or_zero()
+        }
+    }
+
     pub fn update_late_computed_inline_position_if_necessary(&mut self) {
         match self.specific {
             SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) => {
diff --git a/components/layout/inline.rs b/components/layout/inline.rs
index 79d4db2fe5f..07a3068d65b 100644
--- a/components/layout/inline.rs
+++ b/components/layout/inline.rs
@@ -1283,10 +1283,11 @@ impl Flow for InlineFlow {
         // TODO(pcwalton): Cache the line scanner?
         debug!("assign_block_size_inline: floats in: {:?}", self.base.floats);
 
-        // Assign the block-size for the inline fragments.
+        // Assign the block-size and late-computed inline-sizes for the inline fragments.
         let containing_block_block_size =
             self.base.block_container_explicit_block_size.unwrap_or(Au(0));
         for fragment in self.fragments.fragments.iter_mut() {
+            fragment.update_late_computed_replaced_inline_size_if_necessary();
             fragment.assign_replaced_block_size_if_necessary(
                 containing_block_block_size);
         }
diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index 9a9e015e4fb..07182d40582 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -233,6 +233,7 @@ experimental != overconstrained_block.html overconstrained_block_ref.html
 == percent_height.html percent_height_ref.html
 == percentage_height_float_a.html percentage_height_float_ref.html
 == percentage_height_root.html percentage_height_root_ref.html
+== percentage_width_inline_block_a.html percentage_width_inline_block_ref.html
 == png_rgba_colorspace_a.html png_rgba_colorspace_b.html
 == position_abs_cb_with_non_cb_kid_a.html position_abs_cb_with_non_cb_kid_b.html
 == position_abs_height_width_a.html position_abs_height_width_b.html
diff --git a/tests/ref/percentage_width_inline_block_a.html b/tests/ref/percentage_width_inline_block_a.html
new file mode 100644
index 00000000000..0e04a34c0b1
--- /dev/null
+++ b/tests/ref/percentage_width_inline_block_a.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html>
+<head>
+<style>
+section {
+    display: inline-block;
+    width: 100%;
+    background: steelblue;
+    color: white;
+}
+</style>
+</head>
+<body>
+Y<section>X</section>
+</body>
+</html>
+
diff --git a/tests/ref/percentage_width_inline_block_ref.html b/tests/ref/percentage_width_inline_block_ref.html
new file mode 100644
index 00000000000..375c7c8354f
--- /dev/null
+++ b/tests/ref/percentage_width_inline_block_ref.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html>
+<head>
+<style>
+section {
+    width: 100%;
+    background: steelblue;
+    color: white;
+}
+</style>
+</head>
+<body>
+Y<section>X</section>
+</body>
+</html>
+