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

ui/base/events/event_target.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/base/events/event_target.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "ui/base/events/event.h"
@@ skipping 40 matching lines @@
   else
     EventHandler::OnEvent(event);
 }
 
 void EventTarget::OnKeyEvent(KeyEvent* event) {
   CHECK_EQ(this, event->target());
   if (target_handler_)
     target_handler_->OnKeyEvent(event);
 }
 
-EventResult EventTarget::OnMouseEvent(MouseEvent* event) {
+void EventTarget::OnMouseEvent(MouseEvent* event) {
   CHECK_EQ(this, event->target());
-  return target_handler_ ? target_handler_->OnMouseEvent(event) : ER_UNHANDLED;
+  if (target_handler_)
+    target_handler_->OnMouseEvent(event);
 }
 
 void EventTarget::OnScrollEvent(ScrollEvent* event) {
   CHECK_EQ(this, event->target());
   if (target_handler_)
     target_handler_->OnScrollEvent(event);
 }
 
 void EventTarget::OnTouchEvent(TouchEvent* event) {
   CHECK_EQ(this, event->target());
@@ skipping 26 matching lines @@
   while (target) {
     for (EventHandlerList::iterator it = target->post_target_list_.begin(),
         end = target->post_target_list_.end(); it != end; ++it) {
       list->push_back(*it);
     }
     target = target->GetParentTarget();
   }
 }
 
 }  // namespace ui