Fix flakiness in using touch with immersive fullscreen

chrome/browser/ui/views/frame/immersive_mode_controller_ash.cc

Index: chrome/browser/ui/views/frame/immersive_mode_controller_ash.cc
diff --git a/chrome/browser/ui/views/frame/immersive_mode_controller_ash.cc b/chrome/browser/ui/views/frame/immersive_mode_controller_ash.cc
index 7c31ac53f02ccff441b8c9257b7ec76ae685c915..21c2e8ec3facc59369c9fb060a3dbcb441cf5760 100644
--- a/chrome/browser/ui/views/frame/immersive_mode_controller_ash.cc
+++ b/chrome/browser/ui/views/frame/immersive_mode_controller_ash.cc
@@ -461,6 +461,11 @@ void ImmersiveModeControllerAsh::OnMouseEvent(ui::MouseEvent* event) {
   if (!enabled_)
     return;
 
+  // Counterintuitively, we can still get synthesized mouse moves when
+  // aura::client::CursorClient::IsMouseEventsEnabled() == false.
+  if (event->flags() & ui::EF_IS_SYNTHESIZED)
+    return;
+
   if (event->type() != ui::ET_MOUSE_MOVED &&
       event->type() != ui::ET_MOUSE_PRESSED &&
       event->type() != ui::ET_MOUSE_RELEASED &&