cc/blimp: Add synchronization for scroll/scale state.

cc/blimp/layer_tree_host_remote.h

Index: cc/blimp/layer_tree_host_remote.h
diff --git a/cc/blimp/layer_tree_host_remote.h b/cc/blimp/layer_tree_host_remote.h
index 347ffb173058a89f781e093f8350d1b0325bfcc1..da25f0fbaa34844d39e1dc715c101bdfa707c334 100644
--- a/cc/blimp/layer_tree_host_remote.h
+++ b/cc/blimp/layer_tree_host_remote.h
@@ -95,6 +95,11 @@ class CC_EXPORT LayerTreeHostRemote : public LayerTreeHost,
   void SetNextCommitWaitsForActivation() override;
   void ResetGpuRasterizationTracking() override;
 
+  // RemoteCompositorBridgeClient implementation.
+  void BeginMainFrame() override;
+  void ApplyStateUpdateFromClient(
+      const proto::ClientStateUpdate& client_state_update) override;
+
  protected:
   // Protected for testing. Allows tests to inject the LayerTree.
   LayerTreeHostRemote(InitParams* params,
@@ -109,12 +114,6 @@ class CC_EXPORT LayerTreeHostRemote : public LayerTreeHost,
   void SetTaskRunnerProviderForTesting(
       std::unique_ptr<TaskRunnerProvider> task_runner_provider);
 
-  // RemoteCompositorBridgeClient implementation.
-  void BeginMainFrame() override;
-  bool ApplyScrollAndScaleUpdateFromClient(
-      const ScrollOffsetMap& client_scroll_map,
-      float client_page_scale) override;
-
  private:
   enum class FramePipelineStage { NONE, ANIMATE, UPDATE_LAYERS, COMMIT };