Do not request vsync on touch if using synchronous compositor

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index 501eec1b74bf89e6362aa9c060bbb2742d2962e4..00c42590248032132a67dd095580ab9d5552339d 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -1347,7 +1347,7 @@ void RenderWidgetHostViewAndroid::SendTouchEvent(
   // This is good enough as long as the first touch event has Begin semantics
   // and the actual scroll happens on the next vsync.
   // TODO: Is this actually still needed?
-  if (content_view_core_) {
+  if (content_view_core_ && observing_root_window_) {
     content_view_core_->GetWindowAndroid()->RequestVSyncUpdate();
   }
 }