events: Update mouse-event handlers to not return EventResult.

ash/wm/system_modal_container_event_filter.cc

Index: ash/wm/system_modal_container_event_filter.cc
diff --git a/ash/wm/system_modal_container_event_filter.cc b/ash/wm/system_modal_container_event_filter.cc
index da9600f6367c9ae16bdb6d1f57c3d485df7630e7..532bb44acd659ea62ba23d7b6651a2178152e990 100644
--- a/ash/wm/system_modal_container_event_filter.cc
+++ b/ash/wm/system_modal_container_event_filter.cc
@@ -25,11 +25,11 @@ void SystemModalContainerEventFilter::OnKeyEvent(ui::KeyEvent* event) {
     event->StopPropagation();
 }
 
-ui::EventResult SystemModalContainerEventFilter::OnMouseEvent(
+void SystemModalContainerEventFilter::OnMouseEvent(
     ui::MouseEvent* event) {
   aura::Window* target = static_cast<aura::Window*>(event->target());
-  return delegate_->CanWindowReceiveEvents(target) ? ui::ER_UNHANDLED :
-                                                     ui::ER_CONSUMED;
+  if (!delegate_->CanWindowReceiveEvents(target))
+    event->StopPropagation();
 }
 
 }  // namespace internal