mash: Convert OnWindowInputEventAck to use an enum for handled status

components/mus/ws/window_manager_state.h

Index: components/mus/ws/window_manager_state.h
diff --git a/components/mus/ws/window_manager_state.h b/components/mus/ws/window_manager_state.h
index b53885e9dea2cf13cbb07bc94ad353a50669a582..d85199b5f4be81f06963dc6299e29f18a8050499 100644
--- a/components/mus/ws/window_manager_state.h
+++ b/components/mus/ws/window_manager_state.h
@@ -96,9 +96,9 @@ class WindowManagerState : public EventDispatcherDelegate {
   void ProcessEvent(const ui::Event& event);
 
   // Called when the ack from an event dispatched to WindowTree |tree| is
-  // received. When |handled| is true, the client consumed the event.
+  // received.
   // TODO(sky): make this private and use a callback.
-  void OnEventAck(mojom::WindowTree* tree, bool handled);
+  void OnEventAck(mojom::WindowTree* tree, mojom::EventResult result);
 
   // Returns a mojom::Display for the specified display. WindowManager specific
   // values are not set.