[css-flexbox] Correctly resolve percentages in children of stretched flex items

third_party/WebKit/Source/core/layout/LayoutBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 2081 matching lines @@
 
     // Width calculations
     if (treatAsReplaced) {
         computedValues.m_extent = LayoutUnit(logicalWidthLength.value()) + borderAndPaddingLogicalWidth();
     } else if (parent()->isLayoutGrid() && style()->logicalWidth().isAuto() && style()->logicalMinWidth().isAuto() && style()->overflowX() == OVISIBLE && containerLogicalWidth < minPreferredLogicalWidth()) {
         // TODO (lajava) Move this logic to the LayoutGrid class.
         // Implied minimum size of Grid items.
         computedValues.m_extent = constrainLogicalWidthByMinMax(minPreferredLogicalWidth(), containerLogicalWidth, cb);
     } else {
         LayoutUnit containerWidthInInlineDirection = containerLogicalWidth;
-        if (hasPerpendicularContainingBlock)
+        if (hasPerpendicularContainingBlock) {
             containerWidthInInlineDirection = perpendicularContainingBlockLogicalHeight();
+        } else if (styleToUse.logicalWidth().hasPercent() && !isOutOfFlowPositioned() && cb->isFlexItem()) {

[leviw_travelin_and_unemployed, 2016/03/01 01:58:51]

Nit, I may have put the isFlexItem() part first.

[cbiesinger, 2016/03/01 20:36:10]

Done.

+            LayoutUnit stretchedWidth = toLayoutFlexibleBox(cb->parent())->childLogicalHeightForPercentageResolution(*cb);

[leviw_travelin_and_unemployed, 2016/03/01 01:58:51]

Link to spec about why width = height?

[cbiesinger, 2016/03/01 20:36:10]

That was a typo :(

I added a test that hits this case.

+            if (stretchedWidth != LayoutUnit(-1))
+                containerWidthInInlineDirection = stretchedWidth;
+        }
         LayoutUnit preferredWidth = computeLogicalWidthUsing(MainOrPreferredSize, styleToUse.logicalWidth(), containerWidthInInlineDirection, cb);
         computedValues.m_extent = constrainLogicalWidthByMinMax(preferredWidth, containerWidthInInlineDirection, cb);
     }
 
     // Margin calculations.
     computeMarginsForDirection(InlineDirection, cb, containerLogicalWidth, computedValues.m_extent, computedValues.m_margins.m_start,
         computedValues.m_margins.m_end, style()->marginStart(), style()->marginEnd());
 
     if (!hasPerpendicularContainingBlock && containerLogicalWidth && containerLogicalWidth != (computedValues.m_extent + computedValues.m_margins.m_start + computedValues.m_margins.m_end)
         && !isFloating() && !isInline() && !cb->isFlexibleBoxIncludingDeprecated() && !cb->isLayoutGrid()) {
@@ skipping 479 matching lines @@
     cb->addPercentHeightDescendant(const_cast<LayoutBox*>(this));
 
     const ComputedStyle& cbstyle = cb->styleRef();
 
     // A positioned element that specified both top/bottom or that specifies height should be treated as though it has a height
     // explicitly specified that can be used for any percentage computations.
     bool isOutOfFlowPositionedWithSpecifiedHeight = cb->isOutOfFlowPositioned() && (!cbstyle.logicalHeight().isAuto() || (!cbstyle.logicalTop().isAuto() && !cbstyle.logicalBottom().isAuto()));
 
     bool includeBorderPadding = isTable();
 
+    LayoutUnit stretchedFlexHeight(-1);
+    if (cb->isFlexItem())
+        stretchedFlexHeight = toLayoutFlexibleBox(cb->parent())->childLogicalHeightForPercentageResolution(*cb);
+
     if (isHorizontalWritingMode() != cb->isHorizontalWritingMode()) {
         availableHeight = containingBlockChild->containingBlockLogicalWidthForContent();
+    } else if (stretchedFlexHeight != LayoutUnit(-1)) {
+        availableHeight = stretchedFlexHeight;
     } else if (hasOverrideContainingBlockLogicalHeight()) {
         availableHeight = overrideContainingBlockContentLogicalHeight();
     } else if (cb->isTableCell()) {
         if (!skippedAutoHeightContainingBlock) {
             // The second clause in this conditional (after the ||) is to support this line from the
             // definition of height in CSS 2.2:
             // "If the height of the containing block is not specified explicitly (i.e., it depends on
             // content height), and this element is not absolutely positioned, the used height is
             // calculated as if 'auto' was specified."
             // But FF doesn't apply this logic (1) in quirks mode or (2) when "this element" is a table.
@@ skipping 2067 matching lines @@
 }
 
 void LayoutBox::IntrinsicSizingInfo::transpose()
 {
     size = size.transposedSize();
     aspectRatio = aspectRatio.transposedSize();
     std::swap(hasWidth, hasHeight);
 }
 
 } // namespace blink