For flex items, percent paddings should resolve against their respective dimension

Source/core/rendering/RenderBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 Apple Inc. 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 605 matching lines @@
         return ShapeOutsideInfo::isEnabledFor(*this) ? ShapeOutsideInfo::info(*this) : 0;
     }
 
     void markShapeOutsideDependentsForLayout()
     {
         if (isFloating())
             removeFloatingOrPositionedChildFromBlockLists();
     }
 
     virtual void invalidateTreeAfterLayout(const PaintInvalidationState&) OVERRIDE;
+    bool skipContainingBlockForPercentHeightCalculation(const RenderBox* containingBlock) const;
 
 protected:
     virtual void willBeDestroyed() OVERRIDE;
 
     virtual void styleWillChange(StyleDifference, const RenderStyle& newStyle) OVERRIDE;
     virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) OVERRIDE;
     virtual void updateFromStyle() OVERRIDE;
 
     // Returns false if it could not cheaply compute the extent (e.g. fixed background), in which case the returned rect may be incorrect.
     bool getBackgroundPaintedExtent(LayoutRect&) const;
@@ skipping 37 matching lines @@
 private:
     void updateShapeOutsideInfoAfterStyleChange(const RenderStyle&, const RenderStyle* oldStyle);
     void updateGridPositionAfterStyleChange(const RenderStyle*);
 
     bool autoWidthShouldFitContent() const;
     void shrinkToFitWidth(const LayoutUnit availableSpace, const LayoutUnit logicalLeftValue, const LayoutUnit bordersPlusPadding, LogicalExtentComputedValues&) const;
 
     // Returns true if we did a full repaint
     bool repaintLayerRectsForImage(WrappedImagePtr, const FillLayer&, bool drawingBackground);
 
-    bool skipContainingBlockForPercentHeightCalculation(const RenderBox* containingBlock) const;
-
     LayoutUnit containingBlockLogicalWidthForPositioned(const RenderBoxModelObject* containingBlock, bool checkForPerpendicularWritingMode = true) const;
     LayoutUnit containingBlockLogicalHeightForPositioned(const RenderBoxModelObject* containingBlock, bool checkForPerpendicularWritingMode = true) const;
 
     void computePositionedLogicalHeight(LogicalExtentComputedValues&) const;
     void computePositionedLogicalWidthUsing(Length logicalWidth, const RenderBoxModelObject* containerBlock, TextDirection containerDirection,
                                             LayoutUnit containerLogicalWidth, LayoutUnit bordersPlusPadding,
                                             const Length& logicalLeft, const Length& logicalRight, const Length& marginLogicalLeft,
                                             const Length& marginLogicalRight, LogicalExtentComputedValues&) const;
     void computePositionedLogicalHeightUsing(Length logicalHeightLength, const RenderBoxModelObject* containerBlock,
                                              LayoutUnit containerLogicalHeight, LayoutUnit bordersPlusPadding, LayoutUnit logicalHeight,
@@ skipping 85 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != 0))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace WebCore
 
 #endif // RenderBox_h