Handle audio device changes on Windows.

media/audio/win/audio_manager_win.cc

 // 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.
 
 #include "media/audio/audio_io.h"
 
 #include <windows.h>
 #include <objbase.h>  // This has to be before initguid.h
 #include <initguid.h>
 #include <mmsystem.h>
 #include <setupapi.h>
 
-#include "base/basictypes.h"
+#include "base/bind.h"
+#include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/message_loop.h"
 #include "base/path_service.h"
 #include "base/process_util.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "media/audio/audio_util.h"
+#include "media/audio/win/audio_device_listener_win.h"
 #include "media/audio/win/audio_low_latency_input_win.h"
 #include "media/audio/win/audio_low_latency_output_win.h"
 #include "media/audio/win/audio_manager_win.h"
 #include "media/audio/win/audio_unified_win.h"
 #include "media/audio/win/device_enumeration_win.h"
 #include "media/audio/win/wavein_input_win.h"
 #include "media/audio/win/waveout_output_win.h"
+#include "media/base/bind_to_loop.h"
 #include "media/base/limits.h"
 #include "media/base/media_switches.h"
 
 // Libraries required for the SetupAPI and Wbem APIs used here.
 #pragma comment(lib, "setupapi.lib")
 
 // The following are defined in various DDK headers, and we (re)define them
 // here to avoid adding the DDK as a chrome dependency.
 #define DRV_QUERYDEVICEINTERFACE 0x80c
 #define DRVM_MAPPER_PREFERRED_GET 0x2015
@@ skipping 66 matching lines @@
     enumeration_type_ = kWaveEnumeration;
   } else {
     // Use the MMDevice API for device enumeration if Vista or higher.
     enumeration_type_ = kMMDeviceEnumeration;
   }
 
   SetMaxOutputStreamsAllowed(kMaxOutputStreams);
 }
 
 AudioManagerWin::~AudioManagerWin() {
+  // It's safe to post a task here since Shutdown() will wait for all tasks to
+  // complete before returning.
+  GetMessageLoop()->PostTask(FROM_HERE, base::Bind(
+      &AudioManagerWin::DestructOnAudioThread, base::Unretained(this)));
   Shutdown();
 }
 
 bool AudioManagerWin::HasAudioOutputDevices() {
   return (::waveOutGetNumDevs() != 0);
 }
 
 bool AudioManagerWin::HasAudioInputDevices() {
   return (::waveInGetNumDevs() != 0);
 }
 
+void AudioManagerWin::InitializeOnAudioThread() {
+  // AudioDeviceListenerWin must be initialized on a COM thread and should only
+  // be used if WASAPI / Core Audio is supported.
+  if (media::IsWASAPISupported()) {
+    output_device_listener_.reset(new AudioDeviceListenerWin(BindToLoop(
+        GetMessageLoop(), base::Bind(
+            &AudioManagerWin::NotifyAllOutputDeviceChangeListeners,
+            base::Unretained(this)))));
+  }
+}
+
+void AudioManagerWin::DestructOnAudioThread() {
+  output_device_listener_.reset();
+}
+
 string16 AudioManagerWin::GetAudioInputDeviceModel() {
   // Get the default audio capture device and its device interface name.
   DWORD device_id = 0;
   waveInMessage(reinterpret_cast<HWAVEIN>(WAVE_MAPPER),
                 DRVM_MAPPER_PREFERRED_GET,
                 reinterpret_cast<DWORD_PTR>(&device_id), NULL);
   ULONG device_interface_name_size = 0;
   waveInMessage(reinterpret_cast<HWAVEIN>(device_id),
                 DRV_QUERYDEVICEINTERFACESIZE,
                 reinterpret_cast<DWORD_PTR>(&device_interface_name_size), 0);
@@ skipping 203 matching lines @@
     channel_layout = WASAPIAudioOutputStream::HardwareChannelLayout();
   }
 
   // TODO(dalecurtis): This should include hardware bits per channel eventually.
   return AudioParameters(
       AudioParameters::AUDIO_PCM_LOW_LATENCY, channel_layout,
       sample_rate, bits_per_sample, GetAudioHardwareBufferSize());
 }
 
 }  // namespace media