chrome.audio API: treat mute as system wide property

extensions/browser/api/audio/audio_service.h

 // Copyright (c) 2013 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 EXTENSIONS_BROWSER_API_AUDIO_AUDIO_SERVICE_H_
 #define EXTENSIONS_BROWSER_API_AUDIO_AUDIO_SERVICE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 47 matching lines @@
   // Sets the active devices to the devices specified by |device_list|.
   // It can pass in the "complete" active device list of either input
   // devices, or output devices, or both. If only input devices are passed in,
   // it will only change the input devices' active status, output devices will
   // NOT be changed; similarly for the case if only output devices are passed.
   // If the devices specified in |new_active_ids| are already active, they will
   // remain active. Otherwise, the old active devices will be de-activated
   // before we activate the new devices with the same type(input/output).
   virtual void SetActiveDevices(const DeviceIdList& device_list) = 0;
 
-  // Set the muted and volume/gain properties of a device.
-  virtual bool SetDeviceProperties(const std::string& device_id,
-                                   bool muted,
+  // Set the sound level properties (volume or gain) of a device.
+  virtual bool SetDeviceSoundLevel(const std::string& device_id,
                                    int volume,
                                    int gain) = 0;
 
+  // Sets the mute property of a device.
+  virtual bool SetMuteForDevice(const std::string& device_id, bool value) = 0;
+
+  // Sets mute property for audio input (if |is_input| is true) or output (if
+  // |is_input| is false).
+  // Note that the value set here is never persisted on the device - it will be
+  // reset after user session ends.
+  virtual bool SetMute(bool is_input, bool value) = 0;
+
+  // Gets mute property for audio input (if |is_input| is true) or output (if
+  // |is_input| is false).
+  // The mute value is returned via |mute| argument.
+  // The method returns whether the value was successfully fetched.
+  virtual bool GetMute(bool is_input, bool* mute) = 0;
+
  protected:
   AudioService() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AudioService);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_AUDIO_AUDIO_SERVICE_H_