Keep non-key event handling in-house for NativeWidgetMus

ui/views/mus/native_widget_mus.cc

Index: ui/views/mus/native_widget_mus.cc
diff --git a/ui/views/mus/native_widget_mus.cc b/ui/views/mus/native_widget_mus.cc
index 8cf60f7192eb697aca0ebe7cf8df66dd682e1d65..e8d687e9a079df92ea9e8249a8542979890964b4 100644
--- a/ui/views/mus/native_widget_mus.cc
+++ b/ui/views/mus/native_widget_mus.cc
@@ -1321,9 +1321,14 @@ void NativeWidgetMus::OnWindowInputEvent(
   EventAckHandler ack_handler(std::move(*ack_callback));
 
   std::unique_ptr<ui::Event> event = ui::Event::Clone(event_in);
-  // TODO(markdittmer): This should be this->OnEvent(event.get()), but that
-  // can't happen until IME is refactored out of in WindowTreeHostMus.
-  platform_window_delegate()->DispatchEvent(event.get());
+
+  if (!event->IsKeyEvent()) {
+    OnEvent(event.get());
+  } else {
+    // TODO(markdittmer): This should be this->OnEvent(event.get()), but that
+    // can't happen until IME is refactored out of in WindowTreeHostMus.
+    platform_window_delegate()->DispatchEvent(event.get());
+  }
   // NOTE: |this| may be deleted.
 
   ack_handler.set_handled(event->handled());