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 cb2afbcc623807384a97bb66e7a6fb376251af6d..eef99b51c953cc696254018a37f68d42a75681da 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -710,6 +710,13 @@ 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->ProcessRafAlignedInputOnMainThread(routing_id_);
+
   webwidget_->beginFrame(frame_time_sec);
 }