Converts mash to use Shell

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"
 
 namespace ui {
 
 EventTarget::EventTarget()
     : target_handler_(NULL) {
 }
 
 EventTarget::~EventTarget() {
 }
 
 void EventTarget::ConvertEventToTarget(EventTarget* target,
                                        LocatedEvent* event) {
 }
 
 void EventTarget::AddPreTargetHandler(EventHandler* handler) {
+  DCHECK(handler);
   pre_target_list_.push_back(handler);
 }
 
 void EventTarget::PrependPreTargetHandler(EventHandler* handler) {
+  DCHECK(handler);
   pre_target_list_.insert(pre_target_list_.begin(), handler);
 }
 
 void EventTarget::RemovePreTargetHandler(EventHandler* handler) {
   EventHandlerList::iterator find =
       std::find(pre_target_list_.begin(),
                 pre_target_list_.end(),
                 handler);
   if (find != pre_target_list_.end())
     pre_target_list_.erase(find);
 }
 
 void EventTarget::AddPostTargetHandler(EventHandler* handler) {
+  DCHECK(handler);
   post_target_list_.push_back(handler);
 }
 
 void EventTarget::RemovePostTargetHandler(EventHandler* handler) {
   EventHandlerList::iterator find =
       std::find(post_target_list_.begin(),
                 post_target_list_.end(),
                 handler);
   if (find != post_target_list_.end())
     post_target_list_.erase(find);
@@ skipping 28 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