Fixes for re-enabling more MSVC level 4 warnings: ui/ edition

ui/events/event_targeter.cc

 // Copyright (c) 2013 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_targeter.h"
 
 #include "ui/events/event.h"
 #include "ui/events/event_target.h"
 #include "ui/events/event_target_iterator.h"
 
@@ skipping 12 matching lines @@
                                      static_cast<LocatedEvent*>(event));
   }
   return root;
 }
 
 EventTarget* EventTargeter::FindTargetForLocatedEvent(EventTarget* root,
                                                       LocatedEvent* event) {
   scoped_ptr<EventTargetIterator> iter = root->GetChildIterator();
   if (iter) {
     EventTarget* target = root;
-    EventTarget* child = NULL;
-    while ((child = iter->GetNextTarget())) {
+    for (EventTarget* child = iter->GetNextTarget(); child;
+         child = iter->GetNextTarget()) {
       EventTargeter* targeter = child->GetEventTargeter();
       if (!targeter)
         targeter = this;
       if (!targeter->SubtreeShouldBeExploredForEvent(child, *event))
         continue;
       target->ConvertEventToTarget(child, event);
       target = child;
       EventTarget* child_target = targeter ?
           targeter->FindTargetForLocatedEvent(child, event) :
           FindTargetForLocatedEvent(child, event);
@@ skipping 20 matching lines @@
                                           const LocatedEvent& event) const {
   return true;
 }
 
 bool EventTargeter::EventLocationInsideBounds(EventTarget* target,
                                               const LocatedEvent& event) const {
   return true;
 }
 
 }  // namespace ui