[layoutng] Create a more correct constraint space for children

third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc

Index: third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
index f73475e43a4b7ef73881966f2c7e1e216ec1397f..17cd0d8968dd86561232172f5aae72f6da0442dd 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
@@ -23,12 +23,17 @@ NGFragment* NGBlockLayoutAlgorithm::layout(
     const NGConstraintSpace& constraintSpace) {
   LayoutUnit inlineSize =
       computeInlineSizeForFragment(constraintSpace, *m_style);
+  LayoutUnit blockSize =
+      computeBlockSizeForFragment(constraintSpace, *m_style, LayoutUnit(-1));

[ikilpatrick, 2016/08/23 00:49:04]

Is the -1 correct? Should it be LayoutUnit(0) instead?
 - height percentages will get resolved to zero in this case?

(and constraintSpace.blockSize() for quirks mode?) :P

[cbiesinger, 2016/08/23 01:06:54]

They don't get resolved to zero -- indefinite percentages get resolved to auto =
the height of their content.

(You're right about quirks mode, I'll add a TODO)

+  NGConstraintSpace constraint_space_for_children(
+      constraintSpace, NGLogicalSize(inlineSize, blockSize));
 
   HeapVector<Member<const NGFragmentBase>> childFragments;
   LayoutUnit contentSize;
   for (NGBox box : m_boxIterator) {
-    NGBoxMargins childMargins = computeMargins(constraintSpace, *box.style());
-    NGFragment* fragment = box.layout(constraintSpace);
+    NGBoxMargins childMargins =
+        computeMargins(constraint_space_for_children, *box.style());
+    NGFragment* fragment = box.layout(constraint_space_for_children);
     // TODO(layout-ng): Support auto margins
     fragment->setOffset(childMargins.inlineStart,
                         contentSize + childMargins.blockStart);
@@ -37,7 +42,8 @@ NGFragment* NGBlockLayoutAlgorithm::layout(
     childFragments.append(fragment);
   }
 
-  LayoutUnit blockSize =
+  // Recompute the block-axis size now that we know our content size

[ikilpatrick, 2016/08/23 00:49:04]

grammar-Nit: period and end?

(I don't really care if this isn't a rule).

[cbiesinger, 2016/08/23 01:06:54]

Done.

+  blockSize =
       computeBlockSizeForFragment(constraintSpace, *m_style, contentSize);
   NGFragment* returnFragment =
       new NGFragment(inlineSize, blockSize, inlineSize, blockSize,