Adds extension APIs of events on changing volume.

chrome/browser/accessibility_events.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_BROWSER_ACCESSIBILITY_EVENTS_H_
 #define CHROME_BROWSER_ACCESSIBILITY_EVENTS_H_
 #pragma once
 
 #include <string>
 
@@ skipping 237 matching lines @@
 
 // Accessibility information about a menu; this class is used by
 // onMenuOpened, onMenuClosed, and onControlFocused event listeners.
 class AccessibilityMenuInfo : public AccessibilityControlInfo {
  public:
   AccessibilityMenuInfo(Profile* profile, const std::string& menu_name);
 
   virtual const char* type() const;
 };
 
+// Accessibility information about a volume; this class is used by
+// onVolumeUp, onVolumeDown, and onVolumeMute event listeners.
+class AccessibilityVolumeInfo : public AccessibilityControlInfo {

[dmazzoni, 2011/08/24 14:49:02]

I think AccessibilityVolumeInfo shouldn't inherit from AccessibilityControlInfo,
because it's not a control and none of the other events (focus, etc.) apply to
it.

[yoshiki, 2011/08/29 09:16:16]

Done.

+ public:
+  AccessibilityVolumeInfo(Profile* profile, double volume, bool is_mute);

[dmazzoni, 2011/08/24 14:49:02]

Add a comment with the possible volume range, like 0 - 100.

is_mute should be is_muted, throughout.

[yoshiki, 2011/08/29 09:16:16]

Done.

+
+  virtual const char* type() const;
+
+  virtual void SerializeToDict(base::DictionaryValue* dict) const;
+
+ private:
+  double volume_;
+  bool is_mute_;
+};
+
 // Accessibility information about a menu item; this class is used by
 // onControlFocused event listeners.
 class AccessibilityMenuItemInfo : public AccessibilityControlInfo {
  public:
   AccessibilityMenuItemInfo(Profile* profile,
                             const std::string& name,
                             bool has_submenu,
                             int item_index,
                             int item_count);
 
   virtual const char* type() const;
 
   virtual void SerializeToDict(base::DictionaryValue* dict) const;
 
   int item_index() const { return item_index_; }
   int item_count() const { return item_count_; }
   bool has_submenu() const { return has_submenu_; }
 
  private:
   bool has_submenu_;
   // The 0-based index of the current item and the number of total items.
   int item_index_;
   int item_count_;
 };
 
 #endif  // CHROME_BROWSER_ACCESSIBILITY_EVENTS_H_