A few source code cosmetics for notifications.

ui/message_center/notification_types.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_NOTIFICATION_TYPES_H_
 #define UI_MESSAGE_CENTER_NOTIFICATION_TYPES_H_
 
-
-#include <string>
-
 #include "ui/message_center/message_center_export.h"
 
 namespace message_center {
 
 // Keys for optional fields in Notification.
 MESSAGE_CENTER_EXPORT extern const char kPriorityKey[];
 MESSAGE_CENTER_EXPORT extern const char kTimestampKey[];
 MESSAGE_CENTER_EXPORT extern const char kButtonOneTitleKey[];
 MESSAGE_CENTER_EXPORT extern const char kButtonOneIconUrlKey[];
 MESSAGE_CENTER_EXPORT extern const char kButtonTwoTitleKey[];
 MESSAGE_CENTER_EXPORT extern const char kButtonTwoIconUrlKey[];
 MESSAGE_CENTER_EXPORT extern const char kExpandedMessageKey[];
 MESSAGE_CENTER_EXPORT extern const char kImageUrlKey[];
 MESSAGE_CENTER_EXPORT extern const char kItemsKey[];
 MESSAGE_CENTER_EXPORT extern const char kItemTitleKey[];
 MESSAGE_CENTER_EXPORT extern const char kItemMessageKey[];
 // This key should not be used by the extension API handler. It's not allowed
 // to use it there, it's used to cancel timeout for webkit notifications.
 MESSAGE_CENTER_EXPORT extern const char kPrivateNeverTimeoutKey[];
 
 enum NotificationType {
   NOTIFICATION_TYPE_SIMPLE,
   NOTIFICATION_TYPE_BASE_FORMAT,
   NOTIFICATION_TYPE_IMAGE,
   NOTIFICATION_TYPE_MULTIPLE,
-  NOTIFICATION_TYPE_PROGRESS
+  NOTIFICATION_TYPE_PROGRESS  // Notification with progress bar.
 };
 
 enum NotificationPriority {
   MIN_PRIORITY = -2,
   LOW_PRIORITY = -1,
   DEFAULT_PRIORITY = 0,
   HIGH_PRIORITY = 1,
   MAX_PRIORITY = 2,
 
   // Top priority for system-level notifications.. This can't be set from
   // kPriorityKey, instead you have to call SetSystemPriority() of
   // Notification object.
   SYSTEM_PRIORITY = 3,
 };
 
 }  // namespace message_center
 
 #endif // UI_MESSAGE_CENTER_NOTIFICATION_TYPES_H_