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

cc/resources/tile_manager_perftest.cc

Index: cc/resources/tile_manager_perftest.cc
diff --git a/cc/resources/tile_manager_perftest.cc b/cc/resources/tile_manager_perftest.cc
index 211ff017906fd24d0b3eb7e1a41f6ecb732dd9b6..cf653345679a5d69904bc79642872d58a1c71163 100644
--- a/cc/resources/tile_manager_perftest.cc
+++ b/cc/resources/tile_manager_perftest.cc
@@ -65,10 +65,10 @@ class FakeRasterizerImpl : public Rasterizer, public RasterizerTaskClient {
   }
 
   // Overridden from RasterizerTaskClient:
-  virtual SkCanvas* AcquireCanvasForRaster(RasterTask* task) OVERRIDE {
+  virtual RasterBuffer* AcquireBufferForRaster(RasterTask* task) OVERRIDE {
     return NULL;
   }
-  virtual void ReleaseCanvasForRaster(RasterTask* task) OVERRIDE {}
+  virtual void ReleaseBufferForRaster(RasterTask* task) OVERRIDE {}
 
  private:
   RasterTask::Vector completed_tasks_;