Handle audio device changes on Windows.

media/audio/win/audio_low_latency_output_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/win/audio_low_latency_output_win.h"
 
 #include <Functiondiscoverykeys_devpkey.h>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 274 matching lines @@
   }
 
   // Initialize the audio stream between the client and the device using
   // shared or exclusive mode and a lowest possible glitch-free latency.
   // We will enter different code paths depending on the specified share mode.
   hr = InitializeAudioEngine();
   if (FAILED(hr)) {
     return false;
   }
 
-  // Register this client as an IMMNotificationClient implementation.
-  // Only OnDefaultDeviceChanged() and OnDeviceStateChanged() and are
-  // non-trivial.
-  hr = device_enumerator_->RegisterEndpointNotificationCallback(this);
-
   opened_ = true;
-  return SUCCEEDED(hr);
+  return true;
 }
 
 void WASAPIAudioOutputStream::Start(AudioSourceCallback* callback) {
   DCHECK_EQ(GetCurrentThreadId(), creating_thread_id_);
   CHECK(callback);
   CHECK(opened_);
 
   if (render_thread_.get()) {
     CHECK_EQ(callback, source_);
     return;
@@ skipping 92 matching lines @@
   }
 }
 
 void WASAPIAudioOutputStream::Close() {
   DCHECK_EQ(GetCurrentThreadId(), creating_thread_id_);
 
   // It is valid to call Close() before calling open or Start().
   // It is also valid to call Close() after Start() has been called.
   Stop();
 
-  if (opened_ && device_enumerator_) {
-    // De-register the IMMNotificationClient callback interface.
-    HRESULT hr = device_enumerator_->UnregisterEndpointNotificationCallback(
-        this);
-    DLOG_IF(ERROR, FAILED(hr)) << "Failed to disable device notifications: "
-                               << std::hex << hr;
-  }
-
   // Inform the audio manager that we have been closed. This will cause our
   // destruction.
   manager_->ReleaseOutputStream(this);
 }
 
 void WASAPIAudioOutputStream::SetVolume(double volume) {
   DVLOG(1) << "SetVolume(volume=" << volume << ")";
   float volume_float = static_cast<float>(volume);
   if (volume_float < 0.0f || volume_float > 1.0f) {
     return;
@@ skipping 681 matching lines @@
   // are now re-initiated and it is now possible to re-start audio rendering.
 
   // Start rendering again using the new default audio endpoint.
   hr = audio_client_->Start();
 
   restart_rendering_mode_ = false;
   return SUCCEEDED(hr);
 }
 
 }  // namespace media