events: Change gesture-event handler in EventHandler to not return any values.

ui/base/events/event_target.cc

Index: ui/base/events/event_target.cc
diff --git a/ui/base/events/event_target.cc b/ui/base/events/event_target.cc
index 1f8db028fca346a7a3ae66114bc180746e9c3379..6c1d6712913b9d06d23d26d57e9686d24db31d5c 100644
--- a/ui/base/events/event_target.cc
+++ b/ui/base/events/event_target.cc
@@ -65,10 +65,10 @@ EventResult EventTarget::OnTouchEvent(TouchEvent* event) {
                            ER_UNHANDLED;
 }
 
-EventResult EventTarget::OnGestureEvent(GestureEvent* event) {
+void EventTarget::OnGestureEvent(GestureEvent* event) {
   CHECK_EQ(this, event->target());
-  return target_handler_ ? target_handler_->OnGestureEvent(event) :
-                           ER_UNHANDLED;
+  if (target_handler_)
+    target_handler_->OnGestureEvent(event);
 }
 
 void EventTarget::GetPreTargetHandlers(EventHandlerList* list) {