Blink doesn't honor percent heights on children of "align-self:stretch" flex items in a fixed-height

Source/core/rendering/RenderFlexibleBox.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 594 matching lines @@
     return flexBasis.isAuto() || (flexBasis.isPercent() && hasInfiniteLineLength);
 }
 
 bool RenderFlexibleBox::childPreferredMainAxisContentExtentRequiresLayout(RenderBox& child, bool hasInfiniteLineLength) const
 {
     return preferredMainAxisExtentDependsOnLayout(flexBasisForChild(child), hasInfiniteLineLength) && hasOrthogonalFlow(child);
 }
 
 LayoutUnit RenderFlexibleBox::preferredMainAxisContentExtentForChild(RenderBox& child, bool hasInfiniteLineLength, bool relayoutChildren)
 {
-    child.clearOverrideSize();
+    clearLogicalOverrideSize(child);
 
     if (child.style()->hasAspectRatio() || child.isImage() || child.isVideo() || child.isCanvas())
         UseCounter::count(document(), UseCounter::AspectRatioFlexItem);
 
     Length flexBasis = flexBasisForChild(child);
     if (preferredMainAxisExtentDependsOnLayout(flexBasis, hasInfiniteLineLength)) {
         LayoutUnit mainAxisExtent;
         if (hasOrthogonalFlow(child)) {
             if (child.needsLayout() || relayoutChildren) {
                 m_intrinsicSizeAlongMainAxis.remove(&child);
@@ skipping 361 matching lines @@
 }
 
 void RenderFlexibleBox::setLogicalOverrideSize(RenderBox& child, LayoutUnit childPreferredSize)
 {
     if (hasOrthogonalFlow(child))
         child.setOverrideLogicalContentHeight(childPreferredSize - child.borderAndPaddingLogicalHeight());
     else
         child.setOverrideLogicalContentWidth(childPreferredSize - child.borderAndPaddingLogicalWidth());
 }
 
+void RenderFlexibleBox::clearLogicalOverrideSize(RenderBox& child)
+{
+    if (hasOrthogonalFlow(child))
+        child.clearOverrideLogicalContentHeight();
+    else
+        child.clearOverrideLogicalContentWidth();
+}
+
 void RenderFlexibleBox::prepareChildForPositionedLayout(RenderBox& child, LayoutUnit mainAxisOffset, LayoutUnit crossAxisOffset, PositionedLayoutMode layoutMode)
 {
     ASSERT(child.isOutOfFlowPositioned());
     child.containingBlock()->insertPositionedObject(&child);
     RenderLayer* childLayer = child.layer();
     LayoutUnit inlinePosition = isColumnFlow() ? crossAxisOffset : mainAxisOffset;
     if (layoutMode == FlipForRowReverse && style()->flexDirection() == FlowRowReverse)
         inlinePosition = mainAxisExtent() - mainAxisOffset;
     childLayer->setStaticInlinePosition(inlinePosition);
 
@@ skipping 342 matching lines @@
 {
     if (!isColumnFlow() && child.style()->logicalHeight().isAuto()) {
         // FIXME: If the child has orthogonal flow, then it already has an override height set, so use it.
         if (!hasOrthogonalFlow(child)) {
             LayoutUnit heightBeforeStretching = needToStretchChildLogicalHeight(child) ? constrainedChildIntrinsicContentLogicalHeight(child) : child.logicalHeight();
             LayoutUnit stretchedLogicalHeight = heightBeforeStretching + availableAlignmentSpaceForChildBeforeStretching(lineCrossAxisExtent, child);
             ASSERT(!child.needsLayout());
             LayoutUnit desiredLogicalHeight = child.constrainLogicalHeightByMinMax(stretchedLogicalHeight, heightBeforeStretching - child.borderAndPaddingLogicalHeight());
 
             // FIXME: Can avoid laying out here in some cases. See https://webkit.org/b/87905.
-            if (desiredLogicalHeight != child.logicalHeight()) {
+            if (!child.hasOverrideHeight() || ((desiredLogicalHeight - child.borderAndPaddingLogicalHeight()) != child.overrideLogicalContentHeight())) {

[cbiesinger, 2014/09/25 00:50:31]

I think you have to *also* keep desiredLogicalHeight != child.logicalHeight() as
a condition here because there could be a change to the height of the child, in
which case we'd not relayout.

Also, please make desiredLogicalHeight - child.borderAndPaddingLogicalHeight() a
local variable so that the if is easier to read.

[harpreet.sk, 2014/09/25 12:58:57]

Done.

                 child.setOverrideLogicalContentHeight(desiredLogicalHeight - child.borderAndPaddingLogicalHeight());
                 child.setLogicalHeight(0);
                 child.forceChildLayout();
             }
         }
     } else if (isColumnFlow() && child.style()->logicalWidth().isAuto()) {
         // FIXME: If the child doesn't have orthogonal flow, then it already has an override width set, so use it.
         if (hasOrthogonalFlow(child)) {
             LayoutUnit childWidth = std::max<LayoutUnit>(0, lineCrossAxisExtent - crossAxisMarginExtentForChild(child));
             childWidth = child.constrainLogicalWidthByMinMax(childWidth, childWidth, this);
@@ skipping 32 matching lines @@
             ASSERT(child);
             LayoutUnit lineCrossAxisExtent = lineContexts[lineNumber].crossAxisExtent;
             LayoutUnit originalOffset = lineContexts[lineNumber].crossAxisOffset - crossAxisStartEdge;
             LayoutUnit newOffset = contentExtent - originalOffset - lineCrossAxisExtent;
             adjustAlignmentForChild(*child, newOffset - originalOffset);
         }
     }
 }
 
 }