Use reference for FillLayer if possible

Source/core/rendering/RenderBoxModelObject.h

Index: Source/core/rendering/RenderBoxModelObject.h
diff --git a/Source/core/rendering/RenderBoxModelObject.h b/Source/core/rendering/RenderBoxModelObject.h
index 8f0c0b5c7b85178c2c1d3bb1f4df44a4bc9ddffd..d38a814e2500893fd278abec145fc1382a58b7a3 100644
--- a/Source/core/rendering/RenderBoxModelObject.h
+++ b/Source/core/rendering/RenderBoxModelObject.h
@@ -157,7 +157,7 @@ public:
     void paintBorder(const PaintInfo&, const LayoutRect&, const RenderStyle*, BackgroundBleedAvoidance = BackgroundBleedNone, bool includeLogicalLeftEdge = true, bool includeLogicalRightEdge = true);
     bool paintNinePieceImage(GraphicsContext*, const LayoutRect&, const RenderStyle*, const NinePieceImage&, CompositeOperator = CompositeSourceOver);
     void paintBoxShadow(const PaintInfo&, const LayoutRect&, const RenderStyle*, ShadowStyle, bool includeLogicalLeftEdge = true, bool includeLogicalRightEdge = true);
-    void paintFillLayerExtended(const PaintInfo&, const Color&, const FillLayer*, const LayoutRect&, BackgroundBleedAvoidance, InlineFlowBox* = 0, const LayoutSize& = LayoutSize(), CompositeOperator = CompositeSourceOver, RenderObject* backgroundObject = 0);
+    void paintFillLayerExtended(const PaintInfo&, const Color&, const FillLayer&, const LayoutRect&, BackgroundBleedAvoidance, InlineFlowBox* = 0, const LayoutSize& = LayoutSize(), CompositeOperator = CompositeSourceOver, RenderObject* backgroundObject = 0);
 
     virtual bool boxShadowShouldBeAppliedToBackground(BackgroundBleedAvoidance, InlineFlowBox* = 0) const;
 
@@ -244,7 +244,7 @@ protected:
     LayoutPoint adjustedPositionRelativeToOffsetParent(const LayoutPoint&) const;
 
     bool calculateHasBoxDecorations() const;
-    void calculateBackgroundImageGeometry(const RenderLayerModelObject* paintContainer, const FillLayer*, const LayoutRect& paintRect, BackgroundImageGeometry&, RenderObject* = 0) const;
+    void calculateBackgroundImageGeometry(const RenderLayerModelObject* paintContainer, const FillLayer&, const LayoutRect& paintRect, BackgroundImageGeometry&, RenderObject* = 0) const;
     void getBorderEdgeInfo(class BorderEdge[], const RenderStyle*, bool includeLogicalLeftEdge = true, bool includeLogicalRightEdge = true) const;
     bool borderObscuresBackgroundEdge(const FloatSize& contextScale) const;
     bool borderObscuresBackground() const;
@@ -300,7 +300,7 @@ private:
     LayoutUnit computedCSSPadding(const Length&) const;
     virtual bool isBoxModelObject() const OVERRIDE FINAL { return true; }
 
-    IntSize calculateFillTileSize(const FillLayer*, const IntSize& scaledPositioningAreaSize) const;
+    IntSize calculateFillTileSize(const FillLayer&, const IntSize& scaledPositioningAreaSize) const;
 
     RoundedRect getBackgroundRoundedRect(const LayoutRect&, InlineFlowBox*, LayoutUnit inlineBoxWidth, LayoutUnit inlineBoxHeight,
         bool includeLogicalLeftEdge, bool includeLogicalRightEdge) const;