mac: Minor tweaks to notifications code.

ui/message_center/message_center.h

 // 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.
 
 #ifndef UI_MESSAGE_CENTER_MESSAGE_CENTER_H_
 #define UI_MESSAGE_CENTER_MESSAGE_CENTER_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 104 matching lines @@
 
   // Sets the icon image. Icon appears at the top-left of the notification.
   virtual void SetNotificationIcon(const std::string& notification_id,
                                    const gfx::Image& image) = 0;
 
   // Sets the large image for the notifications of type == TYPE_IMAGE. Specified
   // image will appear below of the notification.
   virtual void SetNotificationImage(const std::string& notification_id,
                                     const gfx::Image& image) = 0;
 
-  // Sets the image for the icon of the specific aaction button.
+  // Sets the image for the icon of the specific action button.
   virtual void SetNotificationButtonIcon(const std::string& notification_id,
                                          int button_index,
                                          const gfx::Image& image) = 0;
 
   // Operations happening especially from GUIs: click, expand, disable,
   // and settings.
   // TODO(mukai): settings can be in another class?
   virtual void DisableNotificationsByExtension(const std::string& id) = 0;
   virtual void DisableNotificationsByUrl(const std::string& id) = 0;
   virtual void ShowNotificationSettings(const std::string& id) = 0;
@@ skipping 15 matching lines @@
   MessageCenter();
   virtual ~MessageCenter();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MessageCenter);
 };
 
 }  // namespace message_center
 
 #endif  // UI_MESSAGE_CENTER_MESSAGE_CENTER_H_