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 7518d8f7512e34245ff2fd814d51b01269fab762..3aa04a27e50582a7118089f1efbc31d624391ee5 100644
--- a/cc/resources/tile_manager_perftest.cc
+++ b/cc/resources/tile_manager_perftest.cc
@@ -68,10 +68,10 @@ 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_;