device/bluetooth: Implement Unregister() of BlueotoothAudioSinkChromeOS and disconnection-related c…

device/bluetooth/bluetooth_audio_sink.h

 // Copyright 2014 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 DEVICE_BLUETOOTH_BLUETOOTH_AUDIO_SINK_H_
 #define DEVICE_BLUETOOTH_BLUETOOTH_AUDIO_SINK_H_
 
 #include <stdint.h>
 #include <string>
 #include <vector>
@@ skipping 22 matching lines @@
     STATE_INVALID,  // BluetoothAdapter not presented or not powered.
     STATE_DISCONNECTED,  // Not connected.
     STATE_IDLE,  // Connected but not streaming.
     STATE_PENDING,  // Connected, streaming but not acquired.
     STATE_ACTIVE,  // Connected, streaming and acquired.
   };
 
   // Possible types of error raised by Audio Sink object.
   enum ErrorCode {
     ERROR_UNSUPPORTED_PLATFORM,  // A2DP sink not supported on current platform.
-    ERROR_INVALID_ADAPTER,       // BluetoothAdapter not presented/powered.
-    ERROR_NOT_REGISTERED,        // BluetoothAudioSink not registered.
+    ERROR_INVALID_ADAPTER,  // BluetoothAdapter not present/powered.
+    ERROR_NOT_REGISTERED,  // BluetoothAudioSink not registered.
+    ERROR_NOT_UNREGISTERED,  // BluetoothAudioSink not unregistered.
   };
 
   // Options to configure an A2DP audio sink.
   struct Options {
     Options();
     ~Options();
 
     uint8_t codec;
     std::vector<uint8_t> capabilities;
   };
@@ skipping 19 matching lines @@
 
     // TODO(mcchou): Add method to monitor the availability of audio data during
     // the streaming. This method should associate with BluetoothAudioSink
     // specific IOBuffer wrapping fd, read_mtu and write_mtu.
   };
 
   // The ErrorCallback is used for the methods that can fail in which case it
   // is called.
   typedef base::Callback<void(ErrorCode)> ErrorCallback;
 
+  // Possible volumes for media transport are 0-127, and 128 is used to
+  // represent invalid volume.
+  static const uint16_t kInvalidVolume;
+
   // Unregisters the audio sink. An audio sink will unregister itself
   // automatically in its destructor, but calling Unregister is recommended,
   // since user applications can be notified of an error returned by the call.
   virtual void Unregister(const base::Closure& callback,
                           const ErrorCallback& error_callback) = 0;
 
   // Adds and removes an observer for events on the BluetoothAudioSink object.
   // If monitoring multiple audio sinks, check the |audio_sink| parameter of
   // observer methods to determine which audio sink is issuing the event.
   virtual void AddObserver(Observer* observer) = 0;
   virtual void RemoveObserver(Observer* observer) = 0;
 
   // Getters for state and volume.
   virtual State GetState() const = 0;
+
+  // Returns the current volume level of the audio sink. The possible volumes
+  // are 0-128, where 0-127 are valid volumes and 128 represents invalid volume.

[armansito, 2015/02/24 23:42:09]

nit: Say that if volume is unknown, "kInvalidVolume" is returned instead of
"128" so that callers compare against the constant and not directly against 128.

[Miao, 2015/02/26 02:17:46]

Done.

   virtual uint16_t GetVolume() const = 0;
 
  protected:
   friend class base::RefCounted<BluetoothAudioSink>;
   BluetoothAudioSink();
 
   // The destructor invokes Unregister() to ensure the audio sink will be
   // unregistered even if the user applications fail to do so.
   virtual ~BluetoothAudioSink();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(BluetoothAudioSink);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_BLUETOOTH_BLUETOOTH_AUDIO_SINK_H_