Adds extension APIs of events on changing volume.

chrome/common/chrome_notification_types.h

 // Copyright (c) 2011 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 CHROME_COMMON_CHROME_NOTIFICATION_TYPES_H_
 #define CHROME_COMMON_CHROME_NOTIFICATION_TYPES_H_
 #pragma once
 
 #include "content/common/content_notification_types.h"
 
@@ skipping 608 matching lines @@
   // Notification that a pop-down menu was opened, for propagating
   // to an accessibility extension.
   // Details will be an AccessibilityMenuInfo.
   NOTIFICATION_ACCESSIBILITY_MENU_OPENED,
 
   // Notification that a pop-down menu was closed, for propagating
   // to an accessibility extension.
   // Details will be an AccessibilityMenuInfo.
   NOTIFICATION_ACCESSIBILITY_MENU_CLOSED,
 
+  // Notification that the volume was changed, for propagating
+  // to an accessibility extension.
+  // Details will be an AccessibilityVolumeInfo.
+  NOTIFICATION_ACCESSIBILITY_VOLUME_CHANGED,
+
   // Content Settings --------------------------------------------------------
 
   // Sent when content settings change. The source is a HostContentSettings
   // object, the details are ContentSettingsNotificationsDetails.
   NOTIFICATION_CONTENT_SETTINGS_CHANGED,
 
   // Sent when the collect cookies dialog is shown. The source is a
   // TabSpecificContentSettings object, there are no details.
   NOTIFICATION_COLLECTED_COOKIES_SHOWN,
 
@@ skipping 242 matching lines @@
   // Currently only Content and Chrome define and use notifications.
   // Custom notifications not belonging to Content and Chrome should start
   // from here.
   NOTIFICATION_CHROME_END,
 };
 
 }  // namespace chrome
 
 
 #endif  // CHROME_COMMON_CHROME_NOTIFICATION_TYPES_H_