[VSync Queue] Flush input in CommitComplete()

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index e7b3f6163470bba5d7a5c42a1c31a8cacdb2c698..96c86a52769fe132f320bb8fa7544a224241f650 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -88,6 +88,11 @@ enum class GpuRasterizationStatus {
   MSAA_CONTENT,
 };
 
+enum class ImplThreadPhase {
+  IDLE,
+  INSIDE_IMPL_FRAME,
+};
+
 // LayerTreeHost->Proxy callback interface.
 class LayerTreeHostImplClient {
  public:
@@ -870,6 +875,8 @@ class CC_EXPORT LayerTreeHostImpl
 
   bool touchpad_and_wheel_scroll_latching_enabled_;
 
+  ImplThreadPhase impl_thread_phase_;
+
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };