Move overdraw tracking code from GraphicsContext to CanvasRenderingContext2D

Source/core/html/canvas/CanvasRenderingContext2D.h

Index: Source/core/html/canvas/CanvasRenderingContext2D.h
diff --git a/Source/core/html/canvas/CanvasRenderingContext2D.h b/Source/core/html/canvas/CanvasRenderingContext2D.h
index 87cdbe8bc6b82c543a05017b624f44f0a8d201a2..5e87c0fe13b8a3a7e130c57fc644983909de069b 100644
--- a/Source/core/html/canvas/CanvasRenderingContext2D.h
+++ b/Source/core/html/canvas/CanvasRenderingContext2D.h
@@ -275,6 +275,7 @@ private:
         bool m_realizedFont;
 
         bool m_hasClip;
+        bool m_hasComplexClip;
 
         ClipList m_clipList;
     };
@@ -337,6 +338,20 @@ private:
 
     void validateStateStack();
 
+    enum DrawType {
+        NormalFill,
+        ClipFill, // Normal fill that is already known to cover the current clip
+        UntransformedUnclippedFill
+    };
+
+    enum ImageType {
+        NoImage,
+        OpaqueImage,
+        NonOpaqueImage
+    };
+
+    void checkOverdraw(const SkRect&, const SkPaint*, ImageType, DrawType);
+
     virtual bool is2d() const override { return true; }
     virtual bool isAccelerated() const override;
     virtual bool hasAlpha() const override { return m_hasAlpha; }