device/bluetooth: Add BluetoothAudioSinkChromeOS.

device/bluetooth/bluetooth_audio_sink_chromeos.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_CHROMEOS_H_
+#define DEVICE_BLUETOOTH_BLUETOOTH_AUDIO_SINK_CHROMEOS_H_
+
+#include <stdint.h>
+#include <string>
+#include <vector>
+
+#include "base/observer_list.h"
+#include "chromeos/dbus/bluetooth_media_client.h"
+#include "chromeos/dbus/bluetooth_media_endpoint_service_provider.h"
+#include "chromeos/dbus/bluetooth_media_transport_client.h"
+#include "dbus/object_path.h"
+#include "device/bluetooth/bluetooth_adapter.h"
+#include "device/bluetooth/bluetooth_audio_sink.h"
+#include "device/bluetooth/bluetooth_export.h"
+
+namespace chromeos {
+
+class DEVICE_BLUETOOTH_EXPORT BluetoothAudioSinkChromeOS
+    : public device::BluetoothAudioSink,
+      public device::BluetoothAdapter::Observer,
+      public BluetoothMediaClient::Observer,
+      public BluetoothMediaTransportClient::Observer,
+      public BluetoothMediaEndpointServiceProvider::Delegate {
+ public:
+  // device::BluetoothAudioSink overrides.
+  void AddObserver(BluetoothAudioSink::Observer* observer) override;
+  void RemoveObserver(BluetoothAudioSink::Observer* observer) override;
+  device::BluetoothAudioSink::State GetState() const override;
+  uint16_t GetVolume() const override;
+
+  // device::BluetoothAdapter::Observer overrides.
+  void AdapterPresentChanged(device::BluetoothAdapter* adapter,
+                             bool present) override;
+  void AdapterPoweredChanged(device::BluetoothAdapter* adapter,
+                             bool powered) override;
+
+  // BluetoothMediaClient::Observer overrides.
+  void MediaAdded(const dbus::ObjectPath& object_path) override;
+  void MediaRemoved(const dbus::ObjectPath& object_path) override;
+
+  // BluetoothMediaTransportClient::Observer overrides.
+  void MediaTransportAdded(const dbus::ObjectPath& object_path) override;
+  void MediaTransportRemoved(const dbus::ObjectPath& object_path) override;
+  void MediaTransportPropertyChanged(const dbus::ObjectPath& object_path,
+                                     const std::string& property_name) override;
+
+  // BluetoothMediaEndpointServiceProvider::Delegate overrides.
+  void SetConfiguration(const dbus::ObjectPath& transport_path,
+                        const dbus::MessageReader& properties) override;
+  void SelectConfiguration(
+      const std::vector<uint8_t>& capabilities,
+      const SelectConfigurationCallback& callback) override;
+  void ClearConfiguration(const dbus::ObjectPath& transport_path) override;
+  void Release() override;
+
+ protected:

[armansito, 2014/12/09 00:30:28]

Do these need to be protected? I'd just make Register public.

[Miao, 2014/12/10 04:07:19]

Done. User applications should have no access to
BluetoothAudioSinkChromeOS::Register. As long as user applications don't
downcast the pointer, we shall be fine.

+  // Registers a BluetoothAudioSink. User applications can use |options| to
+  // configure the audio sink. |callback| will be executed if the audio sink is
+  // successfully registered, otherwise |error_callback| will be called.
+  virtual void Register(

[Ben Chan, 2014/12/09 15:28:37]

these methods don't need to be virtual

[Miao, 2014/12/10 04:07:19]

Done.

+      const device::BluetoothAudioSink::Options& options,
+      const device::BluetoothAudioSink::AudioSinkAcquiredCallback& callback,

[armansito, 2014/12/09 00:30:28]

This probably doesn't need to use this callback. I would instead define
|callback| as base::Closure. When you call this in BluetoothAdapterChromeOS, you
can easily bind your BluetoothAudioSinkChromeOS pointer as an argument to the
callback.

[armansito, 2014/12/09 13:30:18]

The name of this callback is too verbose, I would change it to
BluetoothAudioSink::AcquiredCallback.

[Miao, 2014/12/10 04:07:19]

Done.

[Miao, 2014/12/10 04:07:20]

Added a TODO in BluetoothAudioChromeOS.

+      const device::BluetoothAudioSink::ErrorCallback& error_callback);
+
+  // Unregisters a BluetoothAudioSink. |callback| should handle
+  // the clean-up after the audio sink is deleted successfully, otherwise
+  // |error_callback| will be called.
+  virtual void Unregister(

[armansito, 2014/12/09 00:30:28]

Will this be an override of BluetoothAudioSink::Unregister? I'd just define it
correctly here.

[Miao, 2014/12/10 04:07:20]

It's not an override of BluetoothAudioSink::Unregister which has been removed.

+      const base::Closure& callback,
+      const device::BluetoothAudioSink::ErrorCallback& error_callback);
+
+  // Called when the state property of BluetoothMediaTransport has been updated.
+  virtual void StateChanged(const dbus::ObjectPath& object_path,
+                            device::BluetoothAudioSink::State state);
+
+  // Called when the volume property of BluetoothMediaTransport has been
+  // updated.
+  virtual void VolumeChanged(const dbus::ObjectPath& object_path,
+                             uint16_t volume);

[armansito, 2014/12/09 00:30:28]

Make these two methods private (StateChanged & VolumeChanged).

[Miao, 2014/12/10 04:07:19]

Done.

+
+ private:
+  friend class BluetoothAdapterChromeOS;

[armansito, 2014/12/09 00:30:28]

Is the friendship necessary here? You could probably just make the constructor
public since these are all internal classes anyway.

[Miao, 2014/12/10 04:07:20]

Removed the friendship and made constructor public.

+
+  BluetoothAudioSinkChromeOS();

[armansito, 2014/12/09 00:31:20]

The constructor should probably take in a pointer to BluetoothAdapterChromeOS,
since this object will need to observe events from it and needs to obtain its
object path.

[Miao, 2014/12/10 04:07:19]

Done.
The original idea is that BluetoothAdapterChromeOS will call
BluetoothAudioSinkChromeOS::AddObserver to add itself as an observer, but
adding/removing it from the observer list won't be clear in this case. 

+  virtual ~BluetoothAudioSinkChromeOS();

[Ben Chan, 2014/12/09 15:28:37]

~BluetoothAudioSinkChromeOS() override;

[Miao, 2014/12/10 04:07:20]

Done.

+
+  // The connection state between the BluetoothAudioSinkChromeOS and the remote
+  // device;

[Ben Chan, 2014/12/09 15:28:38]

nit:   ;->.

[Miao, 2014/12/10 04:07:19]

Done.

+  device::BluetoothAudioSink::State state_;
+
+  // The volume control by the remote device during the streaming.
+  uint16_t volume_;
+
+  // Object Path of the media object being used.

[Ben Chan, 2014/12/09 15:28:38]

nit: Path -> path

[Miao, 2014/12/10 04:07:19]

Done.

+  dbus::ObjectPath media_path_;
+
+  // Object path of the transport object being used.
+  dbus::ObjectPath transport_path_;
+
+  // List of observers interested in event notifications from us.
+  ObserverList<BluetoothAudioSink::Observer> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(BluetoothAudioSinkChromeOS);
+};
+
+}  // namespace chromeos
+
+#endif  // DEVICE_BLUETOOTH_BLUETOOTH_AUDIO_SINK_CHROMEOS_H_