Avoid forcing layout on children with orthogonal flow

Source/core/rendering/RenderFlexibleBox.h

Index: Source/core/rendering/RenderFlexibleBox.h
diff --git a/Source/core/rendering/RenderFlexibleBox.h b/Source/core/rendering/RenderFlexibleBox.h
index 6e7a8f2b417379e1d4cd84f55f7b697893001623..114984e501cb2d1b88ddf7ba8cbe0af45bf1c245 100644
--- a/Source/core/rendering/RenderFlexibleBox.h
+++ b/Source/core/rendering/RenderFlexibleBox.h
@@ -64,6 +64,7 @@ protected:
     virtual bool supportsPartialLayout() const OVERRIDE { return false; }
 
     virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) OVERRIDE;
+    virtual void removeChild(RenderObject*) OVERRIDE;
 
 private:
     enum FlexSign {
@@ -156,6 +157,9 @@ private:
     void flipForRightToLeftColumn();
     void flipForWrapReverse(const Vector<LineContext>&, LayoutUnit crossAxisStartEdge);
 
+    // This is used to cache the preferred size for orthogonal flow children so we don't have to relayout to get it
+    HashMap<const RenderObject*, LayoutUnit> m_intrinsicSizeAlongMainAxis;
+
     mutable OrderIterator m_orderIterator;
     int m_numberOfInFlowChildrenOnFirstLine;
 };