Add GetAssociatedOutputDeviceID support to pulse.

media/audio/pulse/audio_manager_pulse.cc

 // Copyright 2013 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/pulse/audio_manager_pulse.h"
 
 #include "base/command_line.h"
 #include "base/environment.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
@@ skipping 156 matching lines @@
 }
 
 AudioInputStream* AudioManagerPulse::MakeLowLatencyInputStream(
     const AudioParameters& params,
     const std::string& device_id,
     const LogCallback& log_callback) {
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
   return MakeInputStream(params, device_id);
 }
 
+std::string AudioManagerPulse::GetAssociatedOutputDeviceID(
+    const std::string& input_device_id) {
+  DCHECK(AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread());
+  DCHECK(input_mainloop_);
+  DCHECK(input_context_);
+  if (input_device_id == AudioDeviceDescription::kDefaultDeviceId) {

[Guido Urdaneta, 2016/08/19 14:26:18]

This check is wrong. The default output device is not by definition associated
with the default input device.

The associated output device should be in the same physical device as the input
device.

+    return AudioDeviceDescription::kDefaultDeviceId;
+  }
+
+  std::string input_bus =
+      pulse::GetBusOfInput(input_device_id, input_mainloop_, input_context_);
+  if (input_bus.empty()) {
+    return "";
+  }
+  std::string s = pulse::GetOutputCorrespondingTo(input_bus, input_mainloop_,
+                                                  input_context_);
+  return s;
+}
+
 AudioParameters AudioManagerPulse::GetPreferredOutputStreamParameters(
     const std::string& output_device_id,
     const AudioParameters& input_params) {
   // TODO(tommi): Support |output_device_id|.
   VLOG_IF(0, !output_device_id.empty()) << "Not implemented!";
 
   ChannelLayout channel_layout = CHANNEL_LAYOUT_STEREO;
   int buffer_size = kMinimumOutputBufferSize;
   int bits_per_sample = 16;
   int sample_rate = GetNativeSampleRate();
@@ skipping 152 matching lines @@
 void AudioManagerPulse::SampleRateInfoCallback(pa_context* context,
                                                const pa_server_info* info,
                                                void* user_data) {
   AudioManagerPulse* manager = reinterpret_cast<AudioManagerPulse*>(user_data);
 
   manager->native_input_sample_rate_ = info->sample_spec.rate;
   pa_threaded_mainloop_signal(manager->input_mainloop_, 0);
 }
 
 }  // namespace media