mac: Fix a dangling delegate bug with MCPopupController.

ui/message_center/cocoa/popup_collection.mm

 // 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.
 
 #import "ui/message_center/cocoa/popup_collection.h"
 
 #import "ui/message_center/cocoa/notification_controller.h"
 #import "ui/message_center/cocoa/popup_controller.h"
 #include "ui/message_center/message_center.h"
 #include "ui/message_center/message_center_observer.h"
@@ skipping 174 matching lines @@
     NSRect bounds = [popup bounds];
     bounds.origin.x = x;
     bounds.origin.y = y;
     [popup showWithAnimation:bounds];
     [popups_ addObject:popup];
     messageCenter_->DisplayedNotification(
         notification->id(), message_center::DISPLAY_SOURCE_POPUP);
     return YES;
   }
 
-  // The popup cannot fit on screen, so it has to be released now.
-  [popup release];
+  // The popup cannot fit on screen, so it has to be closed now.
+  [popup close];
   return NO;
 }
 
 - (void)updateNotification:(const std::string&)notificationID {
   // The notification may not be on screen. Create it if needed.
   if ([self indexOfPopupWithNotificationID:notificationID] == NSNotFound) {
     [self layoutNewNotifications];
     return;
   }
 
@@ skipping 182 matching lines @@
   }
 
   pendingUpdateNotificationIDs_.clear();
 
   // Start re-layout of all notifications, so that it readjusts the Y origin of
   // all updated popups and any popups that come below them.
   [self layoutNotifications];
 }
 
 @end