[LayoutNG] Ignore margins when determining if a new-fc will fit in a layout opportunity.

Previously we calculated layout opportunities by shrinking the available child space by the child's margins. This resulted in layout opportunities which were too small, and would push the new formatting context down to the next opportunity. This logic now allows margins to "overhang" a layout opportunity. At the same time I refactored a lot of the code, as we were adding/subtracting margins for different calculations. Hopefully this is more readable! Bug: 1003193 Change-Id: I6c05b050332afe9880ca7d9a5b426b4b94fde3f5 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1808661 Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org> Reviewed-by: Morten Stenshorne <mstensho@chromium.org> Cr-Commit-Position: refs/heads/master@{#698954}

[LayoutNG] Ignore margins when determining if a new-fc will fit in a layout opportunity.
Previously we calculated layout opportunities by shrinking the available child space by the child's margins. This resulted in layout opportunities which were too small, and would push the new formatting context down to the next opportunity. This logic now allows margins to "overhang" a layout opportunity. At the same time I refactored a lot of the code, as we were adding/subtracting margins for different calculations. Hopefully this is more readable! Bug: 1003193 Change-Id: I6c05b050332afe9880ca7d9a5b426b4b94fde3f5 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1808661 Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org> Reviewed-by: Morten Stenshorne <mstensho@chromium.org> Cr-Commit-Position: refs/heads/master@{#698954}
5350ec36 · Ian Kilpatrick · Commit Bot · c412e9bb · 5350ec36 · 5350ec36
Commit 5350ec36 authored Sep 23, 2019 by Ian Kilpatrick Committed by Commit Bot Sep 23, 2019
6 changed files
--- a/third_party/blink/renderer/core/layout/ng/ng_block_layout_algorithm.cc
+++ b/third_party/blink/renderer/core/layout/ng/ng_block_layout_algorithm.cc
--- a/third_party/blink/renderer/core/layout/ng/ng_block_layout_algorithm.h
+++ b/third_party/blink/renderer/core/layout/ng/ng_block_layout_algorithm.h
@@ -173,12 +173,13 @@ class CORE_EXPORT NGBlockLayoutAlgorithm
  // Performs the actual layout of a new formatting context. This may be called
  // multiple times from HandleNewFormattingContext.
-  std::pair<scoped_refptr<const NGLayoutResult>, NGLayoutOpportunity>
+  scoped_refptr<const NGLayoutResult> LayoutNewFormattingContext(
-  LayoutNewFormattingContext(NGLayoutInputNode child,
+      NGLayoutInputNode child,
-                             const NGBreakToken* child_break_token,
+      const NGBreakToken* child_break_token,
-                             const NGInflowChildData&,
+      const NGInflowChildData&,
-                             NGBfcOffset origin_offset,
+      NGBfcOffset origin_offset,
-                             bool abort_if_cleared);
+      bool abort_if_cleared,
+      NGBfcOffset* out_child_bfc_offset);
  // Handle an in-flow child.
  // Returns false if we need to abort layout, because a previously unknown BFC

--- a/third_party/blink/web_tests/FlagExpectations/disable-blink-features=LayoutNG
+++ b/third_party/blink/web_tests/FlagExpectations/disable-blink-features=LayoutNG
@@ -10,6 +10,7 @@ crbug.com/591099 external/wpt/css/CSS2/abspos/hypothetical-box-dynamic.html [ Fa
 crbug.com/591099 external/wpt/css/CSS2/floats/float-nowrap-3.html [ Failure ]
 crbug.com/591099 external/wpt/css/CSS2/floats/floats-line-wrap-shifted-001.html [ Failure ]
 crbug.com/591099 external/wpt/css/CSS2/floats/overhanging-float-paint-order.html [ Failure ]
+crbug.com/591099 external/wpt/css/CSS2/floats/zero-width-floats-positioning.tentative.html [ Failure ]
 ### external/wpt/css/CSS2/floats-clear/
 crbug.com/591099 external/wpt/css/CSS2/floats-clear/no-clearance-adjoining-opposite-float.html [ Failure ]

--- a/third_party/blink/web_tests/external/wpt/css/CSS2/floats/new-fc-beside-float-with-margin-rtl.html
+++ b/third_party/blink/web_tests/external/wpt/css/CSS2/floats/new-fc-beside-float-with-margin-rtl.html
+<!DOCTYPE html>
+<link rel="help" href="https://www.w3.org/TR/CSS22/visuren.html#bfc-next-to-float" title="9.5 Floats">
+<meta name="assert" content="The new formatting context's margin-right does not push it down to the next area.">
+<link rel="match" href="../../reference/ref-filled-green-100px-square.xht">
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+<div style="width: 100px; height: 100px; background: red; direction: rtl;">
+  <div style="float: left; width: 50px; height: 100px; background: green;"></div>
+  <div style="overflow: hidden; height: 100px; margin-left: -20px; background: green;"></div>
+</div>
--- a/third_party/blink/web_tests/external/wpt/css/CSS2/floats/new-fc-beside-float-with-margin.html
+++ b/third_party/blink/web_tests/external/wpt/css/CSS2/floats/new-fc-beside-float-with-margin.html
+<!DOCTYPE html>
+<link rel="help" href="https://www.w3.org/TR/CSS22/visuren.html#bfc-next-to-float" title="9.5 Floats">
+<meta name="assert" content="The new formatting context's margin-right does not push it down to the next area.">
+<link rel="match" href="../../reference/ref-filled-green-100px-square.xht">
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+<div style="width: 100px; height: 100px; background: red;">
+  <div style="float:left; width:50px; height:100px; background:green;"></div>
+  <div style="overflow: hidden; margin-right: 1px; width:50px; height:100px; background:green;"></div>
+</div>
--- a/third_party/blink/web_tests/external/wpt/css/CSS2/floats/zero-width-floats-positioning.html
+++ b/third_party/blink/web_tests/external/wpt/css/CSS2/floats/zero-width-floats-positioning.html
@@ -4,7 +4,7 @@
 <link rel="help" href="https://www.w3.org/TR/CSS22/visudet.html#float-width" title="10.3.5 Floating, non-replaced elements">
 <link rel="match" href="../../reference/ref-filled-green-100px-square-only.html">
 <p>Test passes if there is a filled green square.</p>
-<div style="margin-left: 50px; width: 125px;">
+<div style="width: 125px;">
  <div style="float: left; width: 0px; height: 50px;"></div>
  <div style="float: right; clear: left; width: 25px; height: 50px;"></div>
  <div style="overflow: hidden; margin-left: -50px; height: 100px; background: green;"></div>