Handle audio device changes on Windows.

media/audio/win/audio_device_listener_win.h

Index: media/audio/win/audio_device_listener_win.h
diff --git a/media/audio/win/audio_device_listener_win.h b/media/audio/win/audio_device_listener_win.h
new file mode 100644
index 0000000000000000000000000000000000000000..f1b84f1aed77fb4e3b1662e6018d55f6cf1e53d4
--- /dev/null
+++ b/media/audio/win/audio_device_listener_win.h
@@ -0,0 +1,44 @@
+// 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.
+
+#ifndef MEDIA_AUDIO_WIN_AUDIO_DEVICE_LISTENER_WIN_H_
+#define MEDIA_AUDIO_WIN_AUDIO_DEVICE_LISTENER_WIN_H_
+
+#include <MMDeviceAPI.h>
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/win/scoped_comptr.h"
+#include "media/audio/audio_manager.h"
+#include "media/base/media_export.h"
+
+using base::win::ScopedComPtr;
+
+namespace media {
+
+class MEDIA_EXPORT AudioDeviceListenerWin : public IMMNotificationClient {

[henrika (OOO until Aug 14), 2012/10/21 09:00:20]

Can you add a TODO on me here so I can refactor some parts based on the upcoming
media::win::CoreAudioUtil methods.

[DaleCurtis, 2012/10/23 01:49:42]

Done.

+ public:
+  explicit AudioDeviceListenerWin(AudioManager::AudioDeviceListener* listener);
+  virtual ~AudioDeviceListenerWin();
+
+  STDMETHOD_(ULONG, AddRef)();

[scherkus (not reviewing), 2012/10/22 23:51:05]

emailed chromium-dev about this style

[DaleCurtis, 2012/10/23 01:49:42]

__stdcall seems to be winning. changed.

[henrika (OOO until Aug 14), 2012/10/23 07:38:06]

Thanks for the effort Andrew. 

[henrika (OOO until Aug 14), 2012/10/23 08:21:43]

But as Tommi states, I am also in favor of keeping the COM style.

"+1 For using the macros.  That's the standard and FWIW the #2 approach also
means using Windows specific macros (DWORD, REFIID, et al).

COM is riddled with these macros and types that are specific to COM.  IID,
HRESULT, S_OK, CLASSID, FAILED(), SUCCEEDED(), the list goes on and on.  All of
these are very familiar and immediately recognizable by anyone with COM
experience.  The same goes for STDMETMOD (header file declaration with __stdcall
and the virtual keyword), STDMETHODIMPL (use in the source file, doesn't have
the virtual keyword), macros.  There isn't a lot of COM code in Chromium, so I
don't see the harm in keeping this specific code in line with what developers
that write and maintain it are used to.  It is what it is :-)"

+  STDMETHOD_(ULONG, Release)();
+  STDMETHOD(QueryInterface)(REFIID iid, void** object);
+
+  STDMETHOD(OnPropertyValueChanged)(LPCWSTR device_id, const PROPERTYKEY key);
+  STDMETHOD(OnDeviceAdded)(LPCWSTR device_id);
+  STDMETHOD(OnDeviceRemoved)(LPCWSTR device_id);
+  STDMETHOD(OnDeviceStateChanged)(LPCWSTR device_id, DWORD new_state);
+  STDMETHOD(OnDefaultDeviceChanged)(EDataFlow flow, ERole role,
+                                    LPCWSTR new_default_device_id);
+
+ private:
+  AudioManager::AudioDeviceListener* listener_;
+  ScopedComPtr<IMMDeviceEnumerator> device_enumerator_;
+  std::string default_device_id_;
+};

[scherkus (not reviewing), 2012/10/22 23:51:05]

DISALLOW?

[DaleCurtis, 2012/10/23 01:49:42]

Done.

+
+}  // namespace media
+
+#endif  // MEDIA_AUDIO_WIN_AUDIO_DEVICE_LISTENER_WIN_H_