Use refs for GraphicsContext

third_party/WebKit/Source/platform/graphics/CrossfadeGeneratedImage.h

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 31 matching lines @@
     }
 
     bool usesContainerSize() const override { return false; }
     bool hasRelativeWidth() const override { return false; }
     bool hasRelativeHeight() const override { return false; }
 
     IntSize size() const override { return m_crossfadeSize; }
 
 protected:
     void draw(SkCanvas*, const SkPaint&, const FloatRect&, const FloatRect&, RespectImageOrientationEnum, ImageClampingMode) override;
-    void drawTile(GraphicsContext*, const FloatRect&) final;
+    void drawTile(GraphicsContext&, const FloatRect&) final;
 
     CrossfadeGeneratedImage(Image* fromImage, Image* toImage, float percentage, IntSize crossfadeSize, const IntSize&);
 
 private:
     void drawCrossfade(SkCanvas*, const SkPaint&, ImageClampingMode);
 
     Image* m_fromImage;
     Image* m_toImage;
 
     float m_percentage;
     IntSize m_crossfadeSize;
 };
 
 } // namespace blink
 
 #endif