Implement Main Thread RAF Aligned Input

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 7797b31cf3041a4f58b09656ab2a484985418220..24459d1d92ad8513ecb39911998da716ffbea648 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -706,6 +706,13 @@ void RenderWidget::ApplyViewportDeltas(
 }
 
 void RenderWidget::BeginMainFrame(double frame_time_sec) {
+  RenderThreadImpl* render_thread = RenderThreadImpl::current();
+  // render_thread may be NULL in tests.
+  InputHandlerManager* input_handler_manager =
+      render_thread ? render_thread->input_handler_manager() : NULL;
+  if (input_handler_manager)
+    input_handler_manager->ProcessVSyncAlignedInputOnMainThread(routing_id_);
+
   webwidget_->beginFrame(frame_time_sec);
 }