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

cc/resources/rasterizer.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_RESOURCES_RASTERIZER_H_
 #define CC_RESOURCES_RASTERIZER_H_
 
 #include <vector>
 
 #include "base/callback.h"
 #include "cc/resources/resource_format.h"
 #include "cc/resources/task_graph_runner.h"
 
 class SkCanvas;
 
 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:
   virtual ~RasterizerTaskClient() {}
 };
 
 class CC_EXPORT RasterizerTask : public Task {
  public:
   typedef std::vector<scoped_refptr<RasterizerTask> > Vector;
 
@@ skipping 122 matching lines @@
   // Check for completed tasks and dispatch reply callbacks.
   virtual void CheckForCompletedTasks() = 0;
 
  protected:
   virtual ~Rasterizer() {}
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_RASTERIZER_H_