Add GetOutputStreamParameters, GetAssociatedOutputDeviceID to AudioManager.

media/audio/win/core_audio_util_win.h

 // Copyright (c) 2012 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.
 
 // Utility methods for the Core Audio API on Windows.
 // Always ensure that Core Audio is supported before using these methods.
 // Use media::CoreAudioIsSupported() for this purpose.
 // Also, all methods must be called on a valid COM thread. This can be done
 // by using the base::win::ScopedCOMInitializer helper class.
 
@@ skipping 41 matching lines @@
 
   // Creates an IMMDeviceEnumerator interface which provides methods for
   // enumerating audio endpoint devices.
   static ScopedComPtr<IMMDeviceEnumerator> CreateDeviceEnumerator();
 
   // Creates a default endpoint device that is specified by a data-flow
   // direction and role, e.g. default render device.
   static ScopedComPtr<IMMDevice> CreateDefaultDevice(
       EDataFlow data_flow, ERole role);
 
+  // Returns the device id of the default output device or an empty string
+  // if no such device exists or if the default device has been disabled.

[henrika (OOO until Aug 14), 2013/09/04 11:11:40]

Nit, ...or no output devices exists.

[tommi (sloooow) - chröme, 2013/09/04 13:06:55]

The comment already says "or an empty string if no such device exists" so I
think that's covered :)

+  static std::string GetDefaultOutputDeviceID();
+
   // Creates an endpoint device that is specified by a unique endpoint device-
   // identification string.
   static ScopedComPtr<IMMDevice> CreateDevice(const std::string& device_id);
 
   // Returns the unique ID and user-friendly name of a given endpoint device.
   // Example: "{0.0.1.00000000}.{8db6020f-18e3-4f25-b6f5-7726c9122574}", and
   //          "Microphone (Realtek High Definition Audio)".
   static HRESULT GetDeviceName(IMMDevice* device, AudioDeviceName* name);
 
   // Returns the device ID/path of the controller (a.k.a. physical device that
@@ skipping 128 matching lines @@
 
  private:
   CoreAudioUtil() {}
   ~CoreAudioUtil() {}
   DISALLOW_COPY_AND_ASSIGN(CoreAudioUtil);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_WIN_CORE_AUDIO_UTIL_WIN_H_