Handle audio device changes on Windows.

media/audio/win/audio_low_latency_output_win.cc

Index: media/audio/win/audio_low_latency_output_win.cc
diff --git a/media/audio/win/audio_low_latency_output_win.cc b/media/audio/win/audio_low_latency_output_win.cc
index 966f0775dbe43e8b47f8bc3743b8232901ae5fdd..c353cb83a123e05d44bc3f7d264b1fd8bfc6f153 100644
--- a/media/audio/win/audio_low_latency_output_win.cc
+++ b/media/audio/win/audio_low_latency_output_win.cc
@@ -292,13 +292,8 @@ bool WASAPIAudioOutputStream::Open() {
     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) {
@@ -411,14 +406,6 @@ void WASAPIAudioOutputStream::Close() {
   // 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);