Devirtualize isStretchingChildren

Source/core/rendering/RenderDeprecatedFlexibleBox.h

Index: Source/core/rendering/RenderDeprecatedFlexibleBox.h
diff --git a/Source/core/rendering/RenderDeprecatedFlexibleBox.h b/Source/core/rendering/RenderDeprecatedFlexibleBox.h
index 8094d04d31ee2ae12b16f2551fae7e719b86ee83..91ba298e7b89ac26c02fb75758ca01eec2b23fc9 100644
--- a/Source/core/rendering/RenderDeprecatedFlexibleBox.h
+++ b/Source/core/rendering/RenderDeprecatedFlexibleBox.h
@@ -46,7 +46,7 @@ public:
 
     virtual bool avoidsFloats() const OVERRIDE { return true; }
     virtual bool isDeprecatedFlexibleBox() const OVERRIDE { return true; }
-    virtual bool isStretchingChildren() const OVERRIDE { return m_stretchingChildren; }
+    bool isStretchingChildren() const { return m_stretchingChildren; }
     virtual bool canCollapseAnonymousBlockChild() const OVERRIDE { return false; }
 
     void placeChild(RenderBox* child, const LayoutPoint& location);
@@ -70,6 +70,8 @@ private:
     void clearLineClamp();
 };
 
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderDeprecatedFlexibleBox, isDeprecatedFlexibleBox());
+
 } // namespace WebCore
 
 #endif // RenderDeprecatedFlexibleBox_h