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

cc/resources/resource_provider.h

Index: cc/resources/resource_provider.h
diff --git a/cc/resources/resource_provider.h b/cc/resources/resource_provider.h
index e44b75e87649912d184477cce6b70879d9adc03a..788858779b55836afbb87fbc275632690683ddde 100644
--- a/cc/resources/resource_provider.h
+++ b/cc/resources/resource_provider.h
@@ -20,6 +20,7 @@
 #include "cc/base/cc_export.h"
 #include "cc/output/context_provider.h"
 #include "cc/output/output_surface.h"
+#include "cc/resources/rasterizer.h"
 #include "cc/resources/release_callback.h"
 #include "cc/resources/resource_format.h"
 #include "cc/resources/return_callback.h"
@@ -316,7 +317,7 @@ class CC_EXPORT ResourceProvider {
   // Returns a canvas for gpu rasterization.
   // Call Unmap before the resource can be read or used for compositing.
   // It is used for direct gpu rasterization.
-  SkCanvas* MapGpuRasterBuffer(ResourceId id);
+  RasterCanvas* MapGpuRasterBuffer(ResourceId id);
   void UnmapGpuRasterBuffer(ResourceId id);
 
   // Returns a canvas backed by an image buffer. UnmapImageRasterBuffer
@@ -325,7 +326,7 @@ class CC_EXPORT ResourceProvider {
   // which is internally bound to the underlying resource when read.
   // Call Unmap before the resource can be read or used for compositing.
   // It is used by ImageRasterWorkerPool.
-  SkCanvas* MapImageRasterBuffer(ResourceId id);
+  RasterCanvas* MapImageRasterBuffer(ResourceId id);
   bool UnmapImageRasterBuffer(ResourceId id);
 
   // Returns a canvas backed by pixel buffer. UnmapPixelRasterBuffer
@@ -335,7 +336,7 @@ class CC_EXPORT ResourceProvider {
   // It is used by PixelRasterWorkerPool.
   void AcquirePixelRasterBuffer(ResourceId id);
   void ReleasePixelRasterBuffer(ResourceId id);
-  SkCanvas* MapPixelRasterBuffer(ResourceId id);
+  RasterCanvas* MapPixelRasterBuffer(ResourceId id);
   bool UnmapPixelRasterBuffer(ResourceId id);
 
   // Asynchronously update pixels from acquired pixel buffer.
@@ -445,11 +446,11 @@ class CC_EXPORT ResourceProvider {
   };
   typedef base::hash_map<ResourceId, Resource> ResourceMap;
 
-  class RasterBuffer {
+  class RasterBuffer : public RasterCanvas {

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

Do we need both a RasterBuffer and a RasterCanvas interface? I'm not a fan of
the existing use of inheritance for RasterBuffer code reuse. Maybe we can make
RasterBuffer the public interface used by raster tasks and use a more
appropriate mechanism for code reuse in RP.   

[auygun, 2014/08/11 14:03:00]

I'll try to do that. Looks like RasterBuffer can easily be removed. I don't
think lock/unlock functions need to be virtuals.

    public:
     virtual ~RasterBuffer();
 
-    SkCanvas* LockForWrite();
+    void LockForWrite();
     // Returns true if canvas was written to while locked.
     bool UnlockForWrite();
 
@@ -464,7 +465,6 @@ class CC_EXPORT ResourceProvider {
    private:
     const Resource* resource_;
     ResourceProvider* resource_provider_;
-    SkCanvas* locked_canvas_;
     int canvas_save_count_;
   };
 
@@ -478,6 +478,7 @@ class CC_EXPORT ResourceProvider {
    protected:
     virtual SkCanvas* DoLockForWrite() OVERRIDE;
     virtual bool DoUnlockForWrite() OVERRIDE;
+    virtual void Flush() OVERRIDE {}
     skia::RefPtr<SkSurface> CreateSurface();
 
    private:
@@ -498,6 +499,7 @@ class CC_EXPORT ResourceProvider {
 
     virtual SkCanvas* DoLockForWrite() OVERRIDE;
     virtual bool DoUnlockForWrite() OVERRIDE;
+    virtual void Flush() OVERRIDE;
 
     virtual uint8_t* MapBuffer(int* stride) = 0;
     virtual void UnmapBuffer() = 0;