Move logic from NativeImageSkia to GraphicsContext and SkiaUtils

Source/platform/graphics/GraphicsContext.h

Index: Source/platform/graphics/GraphicsContext.h
diff --git a/Source/platform/graphics/GraphicsContext.h b/Source/platform/graphics/GraphicsContext.h
index d6e8985933b5592f797b812e0a6424ac4c16b3d9..e5bd420a8a66d0a973a71bf1e4294b635df4b825 100644
--- a/Source/platform/graphics/GraphicsContext.h
+++ b/Source/platform/graphics/GraphicsContext.h
@@ -237,7 +237,7 @@ public:
     AnnotationModeFlags annotationMode() const { return m_annotationMode; }
     void setAnnotationMode(const AnnotationModeFlags mode) { m_annotationMode = mode; }
 
-    SkColorFilter* colorFilter();
+    SkColorFilter* colorFilter() const;
     void setColorFilter(ColorFilter);
     // ---------- End state management methods -----------------
 
@@ -411,6 +411,13 @@ public:
     void beginAnnotation(const AnnotationList&);
     void endAnnotation();
 
+    void preparePaint(

[jbroman, 2014/07/23 15:48:59]

drive-by: please use a more descriptive name than "preparePaint". What kind of
paint is this preparing, and where should it be used? It's not obvious what
srcRect and destRect mean in this context.

[Rémi Piotaix, 2014/07/23 17:28:22]

Done.

+        SkPaint*,
+        const SkRect& srcRect,
+        const SkRect& destRect,
+        CompositeOperator,
+        blink::WebBlendMode,
+        bool isLazyDecoded = false) const;
 private:
     const GraphicsContextState* immutableState() const { return m_paintState; }