mash: Convert OnWindowInputEventAck to use an enum for handled status

components/mus/ws/window_tree.cc

Index: components/mus/ws/window_tree.cc
diff --git a/components/mus/ws/window_tree.cc b/components/mus/ws/window_tree.cc
index ed05e243550eee04060839076904650c0b889b1f..863a3a13e61a2095581b0f08fac3b089e39daa76 100644
--- a/components/mus/ws/window_tree.cc
+++ b/components/mus/ws/window_tree.cc
@@ -1219,7 +1219,8 @@ void WindowTree::SetImeVisibility(Id transport_window_id,
   }
 }
 
-void WindowTree::OnWindowInputEventAck(uint32_t event_id, bool handled) {
+void WindowTree::OnWindowInputEventAck(uint32_t event_id,
+                                       mojom::EventResult result) {
   if (event_ack_id_ == 0 || event_id != event_ack_id_) {
     // TODO(sad): Something bad happened. Kill the client?
     NOTIMPLEMENTED() << "Wrong event acked.";
@@ -1229,7 +1230,7 @@ void WindowTree::OnWindowInputEventAck(uint32_t event_id, bool handled) {
   WindowManagerState* event_source_wms = event_source_wms_;
   event_source_wms_ = nullptr;
   if (event_source_wms)
-    event_source_wms->OnEventAck(this, handled);
+    event_source_wms->OnEventAck(this, result);
 
   if (!event_queue_.empty()) {
     DCHECK(!event_ack_id_);