Looking up device id by session id for AudioRendererMixerInput

media/audio/audio_output_device.cc

Index: media/audio/audio_output_device.cc
diff --git a/media/audio/audio_output_device.cc b/media/audio/audio_output_device.cc
index 7044e9ae770649c0477b9b37af56eca6fff01abb..5ba556578de7bca6207186af63504de4e6b081a4 100644
--- a/media/audio/audio_output_device.cc
+++ b/media/audio/audio_output_device.cc
@@ -293,7 +293,8 @@ void AudioOutputDevice::OnStateChanged(AudioOutputIPCDelegateState state) {
 
 void AudioOutputDevice::OnDeviceAuthorized(
     OutputDeviceStatus device_status,
-    const media::AudioParameters& output_params) {
+    const media::AudioParameters& output_params,
+    const std::string& matched_device_id) {
   DCHECK(task_runner()->BelongsToCurrentThread());
   DCHECK_EQ(state_, AUTHORIZING);
 
@@ -316,6 +317,14 @@ void AudioOutputDevice::OnDeviceAuthorized(
     }
     if (start_on_authorized_)
       CreateStreamOnIOThread(audio_parameters_);
+
+    // Matching can take place only if |session_id_| is specified and
+    // |device_id_| is not, however, it's possible not to have a matched device
+    // even in this case. It means |session_id_| failed and the default device

[Henrik Grunell, 2016/03/08 21:09:57]

What does "|session_id_| failed" mean?

[o1ka, 2016/04/05 15:13:38]

Done.

+    // is used.
+    DCHECK((session_id_ && device_id_.empty()) ? true
+                                               : matched_device_id_.empty());
+    matched_device_id_ = matched_device_id;

[o1ka, 2016/04/05 15:13:38]

This races with a getter: |matched_device_id_| should be set before
did_receive_auth_.Signal().

   } else {
     // Closing IPC forces a Signal(), so no clients are locked waiting
     // indefinitely after this method returns.
@@ -387,6 +396,12 @@ void AudioOutputDevice::WillDestroyCurrentMessageLoop() {
   ShutDownOnIOThread();
 }
 
+std::string AudioOutputDevice::GetDeviceId() {
+  CHECK(!task_runner()->BelongsToCurrentThread());
+  did_receive_auth_.Wait();
+  return (device_id_.empty() && session_id_) ? matched_device_id_ : device_id_;
+}
+
 // AudioOutputDevice::AudioThreadCallback
 
 AudioOutputDevice::AudioThreadCallback::AudioThreadCallback(