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>
+#include "base/compiler_specific.h"
 
-class AccessibilityControlInfo;
+class AccessibilityEventInfo;
 class Profile;
 
 namespace base {
 class DictionaryValue;
 }
 
 // Use the NotificationService to post the given accessibility
-// notification type with AccessibilityControlInfo details to any
+// notification type with AccessibilityEventInfo details to any
 // listeners.  Will not send if the profile's pause level is nonzero
 // (using profile->PauseAccessibilityEvents).
 void SendAccessibilityNotification(
-    int type, AccessibilityControlInfo* info);
+    int type, AccessibilityEventInfo* info);
+void SendAccessibilityVolumeNotification(double volume, bool is_muted);
+
+// Abstract parent class for accessibility event information passed to event
+// listeners.
+class AccessibilityEventInfo {
+ public:
+  virtual ~AccessibilityEventInfo() {}
+
+  // Serialize this class as a DictionaryValue that can be converted to
+  // a JavaScript object.
+  virtual void SerializeToDict(base::DictionaryValue* dict) const = 0;
+
+  Profile* profile() const { return profile_; }
+
+ protected:
+  explicit AccessibilityEventInfo(Profile* profile) : profile_(profile) {}
+
+  // The profile this control belongs to.
+  Profile* profile_;
+};
 
 // Abstract parent class for accessibility information about a control
 // passed to event listeners.
-class AccessibilityControlInfo {
+class AccessibilityControlInfo : public AccessibilityEventInfo {
  public:
   virtual ~AccessibilityControlInfo();
 
   // Serialize this class as a DictionaryValue that can be converted to
   // a JavaScript object.
-  virtual void SerializeToDict(base::DictionaryValue* dict) const;
+  virtual void SerializeToDict(base::DictionaryValue* dict) const OVERRIDE;
 
   // Return the specific type of this control, which will be one of the
   // string constants defined in extension_accessibility_api_constants.h.
   virtual const char* type() const = 0;
 
-  Profile* profile() const { return profile_; }
-
   const std::string& name() const { return name_; }
 
  protected:
   AccessibilityControlInfo(Profile* profile, const std::string& control_name);
 
-  // The profile this control belongs to.
-  Profile* profile_;
-
   // The name of the control, like "OK" or "Password".
   std::string name_;
 };
 
 // Accessibility information about a window passed to onWindowOpened
 // and onWindowClosed event listeners.
 class AccessibilityWindowInfo : public AccessibilityControlInfo {
  public:
   AccessibilityWindowInfo(Profile* profile, const std::string& window_name);
 
@@ skipping 189 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 AccessibilityEventInfo {
+ public:
+  // |volume| must range between 0 to 100.
+  AccessibilityVolumeInfo(Profile* profile, double volume, bool is_muted);
+
+  virtual void SerializeToDict(base::DictionaryValue* dict) const;
+
+ private:
+  double volume_;
+  bool is_muted_;
+};
+
 // 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_