Use refs for GraphicsContext

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

Index: third_party/WebKit/Source/platform/graphics/GeneratedImage.h
diff --git a/third_party/WebKit/Source/platform/graphics/GeneratedImage.h b/third_party/WebKit/Source/platform/graphics/GeneratedImage.h
index 643312cc3b1626705ca83fdc881180e196276586..a02ff7d4dfc68b08bb1cf3d5fd174f0d9b30a078 100644
--- a/third_party/WebKit/Source/platform/graphics/GeneratedImage.h
+++ b/third_party/WebKit/Source/platform/graphics/GeneratedImage.h
@@ -49,7 +49,7 @@ public:
     PassRefPtr<SkImage> imageForCurrentFrame() override;
 
 protected:
-    void drawPattern(GraphicsContext*, const FloatRect&,
+    void drawPattern(GraphicsContext&, const FloatRect&,
         const FloatSize&, const FloatPoint&, SkXfermode::Mode,
         const FloatRect&, const FloatSize& repeatSpacing) final;
 
@@ -58,7 +58,7 @@ protected:
 
     GeneratedImage(const IntSize& size) : m_size(size) { }
 
-    virtual void drawTile(GraphicsContext*, const FloatRect&) = 0;
+    virtual void drawTile(GraphicsContext&, const FloatRect&) = 0;
 
     IntSize m_size;
 };