cc: Unify use of DidSwapBuffers() and did_request_swap

cc/test/layer_tree_test.h

Index: cc/test/layer_tree_test.h
diff --git a/cc/test/layer_tree_test.h b/cc/test/layer_tree_test.h
index a4a32d239554bad19f74e7e781a99635d2d12feb..e7d618badaeef5d84df7f1a16c6d937472103db0 100644
--- a/cc/test/layer_tree_test.h
+++ b/cc/test/layer_tree_test.h
@@ -44,10 +44,10 @@ class TestHooks : public AnimationDelegate {
   virtual void DidActivateTreeOnThread(LayerTreeHostImpl* host_impl) {}
   virtual void InitializedRendererOnThread(LayerTreeHostImpl* host_impl,
                                            bool success) {}
-  virtual DrawSwapReadbackResult::DrawResult PrepareToDrawOnThread(
+  virtual DrawResult PrepareToDrawOnThread(
       LayerTreeHostImpl* host_impl,
       LayerTreeHostImpl::FrameData* frame_data,
-      DrawSwapReadbackResult::DrawResult draw_result);
+      DrawResult draw_result);
   virtual void DrawLayersOnThread(LayerTreeHostImpl* host_impl) {}
   virtual void SwapBuffersOnThread(LayerTreeHostImpl* host_impl, bool result) {}
   virtual void SwapBuffersCompleteOnThread(LayerTreeHostImpl* host_impl) {}