Refactoring to make adding ink drop animations easier

ui/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/events/event_target.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "ui/events/event.h"
@@ skipping 38 matching lines @@
                 post_target_list_.end(),
                 handler);
   if (find != post_target_list_.end())
     post_target_list_.erase(find);
 }
 
 bool EventTarget::IsPreTargetListEmpty() const {
   return pre_target_list_.empty();
 }
 
+EventHandler* EventTarget::SetTargetHandler(EventHandler* target_handler) {
+  EventHandler* original_target_handler = target_handler_;
+  target_handler_ = target_handler;
+  return original_target_handler;
+}
+
 void EventTarget::OnEvent(Event* event) {
   CHECK_EQ(this, event->target());
   if (target_handler_)
     target_handler_->OnEvent(event);
   else
     EventHandler::OnEvent(event);
 }
 
 void EventTarget::OnKeyEvent(KeyEvent* event) {
   CHECK_EQ(this, event->target());
@@ skipping 44 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