cc: Do bitmap conversion for RasterBuffer in the worker thread.

cc/resources/rasterizer.h

Index: cc/resources/rasterizer.h
diff --git a/cc/resources/rasterizer.h b/cc/resources/rasterizer.h
index 17cc94ed6fa8b82f1a17e565f59e0847b2743657..3681860d7176c339297cd8b5cd80fbd23f42aa21 100644
--- a/cc/resources/rasterizer.h
+++ b/cc/resources/rasterizer.h
@@ -17,10 +17,24 @@ namespace cc {
 class ImageDecodeTask;
 class RasterTask;
 class Resource;
+class ResourceProvider;
+
+class RasterCanvas {

[reveman, 2014/08/11 11:46:20]

I think this interface deserves it's own file.

[auygun, 2014/08/11 15:45:43]

Done.

+ public:
+  virtual ~RasterCanvas();

[reveman, 2014/08/11 11:46:21]

can this be protected?

[auygun, 2014/08/11 15:45:43]

Done.

+
+  SkCanvas* GetSkCanvas() { return locked_canvas_; }

[reveman, 2014/08/11 11:46:21]

Can we make this interface completely abstract? Only pure virtual functions?

[auygun, 2014/08/11 15:45:43]

Done.

+  virtual void Flush() = 0;
+
+ protected:
+  RasterCanvas();
+
+  SkCanvas* locked_canvas_;
+};
 
 class CC_EXPORT RasterizerTaskClient {
  public:
-  virtual SkCanvas* AcquireCanvasForRaster(RasterTask* task) = 0;
+  virtual RasterCanvas* AcquireCanvasForRaster(RasterTask* task) = 0;
   virtual void ReleaseCanvasForRaster(RasterTask* task) = 0;
 
  protected: