Allow AudioManagerCras enumerate audio devices from CRAS not just defaults

media/audio/cras/audio_manager_cras.cc

Index: media/audio/cras/audio_manager_cras.cc
diff --git a/media/audio/cras/audio_manager_cras.cc b/media/audio/cras/audio_manager_cras.cc
index 7fdf07241aa2b5d2c97aad546af36562ffe20b62..e1f5bb9d6eefe51cab9bb3284a3dab5e46712b20 100644
--- a/media/audio/cras/audio_manager_cras.cc
+++ b/media/audio/cras/audio_manager_cras.cc
@@ -15,6 +15,7 @@
 #include "base/metrics/histogram.h"
 #include "base/nix/xdg_util.h"
 #include "base/stl_util.h"
+#include "base/strings/string_number_conversions.h"
 #include "chromeos/audio/audio_device.h"
 #include "chromeos/audio/cras_audio_handler.h"
 #include "media/audio/audio_device_description.h"
@@ -65,13 +66,6 @@ bool IsBeamformingDefaultEnabled() {
          "Enabled";
 }
 
-void AddDefaultDevice(AudioDeviceNames* device_names) {
-  DCHECK(device_names->empty());
-
-  // Cras will route audio from a proper physical device automatically.
-  device_names->push_back(AudioDeviceName::CreateDefault());
-}
-
 // Returns a mic positions string if the machine has a beamforming capable
 // internal mic and otherwise an empty string.
 std::string MicPositions() {
@@ -155,23 +149,39 @@ void AudioManagerCras::ShowAudioInputSettings() {
   NOTIMPLEMENTED();
 }
 
-void AudioManagerCras::GetAudioInputDeviceNames(
-    AudioDeviceNames* device_names) {
+void AudioManagerCras::GetAudioDeviceNamesImpl(bool is_input,
+                                               AudioDeviceNames* device_names) {
   DCHECK(device_names->empty());
-
-  mic_positions_ = ParsePointsFromString(MicPositions());
   // At least two mic positions indicates we have a beamforming capable mic
   // array. Add the virtual beamforming device to the list. When this device is
   // queried through GetInputStreamParameters, provide the cached mic positions.
-  if (mic_positions_.size() > 1)
+  bool should_add_beamforming_devices = is_input && mic_positions_.size() > 1;
+  if (should_add_beamforming_devices)
     AddBeamformingDevices(device_names);
-  else
-    AddDefaultDevice(device_names);
+  chromeos::AudioDeviceList devices;
+  chromeos::CrasAudioHandler::Get()->GetAudioDevices(&devices);
+  for (const auto& device : devices) {
+    if (device.is_input == is_input && device.is_for_simple_usage()) {
+      media::AudioDeviceName device_name;
+      device_name.device_name = device.device_name;
+      device_name.unique_id = base::Uint64ToString(device.id);
+      device_names->push_back(device_name);

[DaleCurtis, 2016/07/06 18:58:52]

Does emplace_back(device.device_name, base::Uint64ToString(device.id)) work?

[Qiang(Joe) Xu, 2016/07/07 00:32:45]

done. tks.

+    }
+  }
+  if (!device_names->empty() && !should_add_beamforming_devices) {
+    device_names->push_front(media::AudioDeviceName::CreateDefault());

[DaleCurtis, 2016/07/06 18:58:53]

Just do this first to avoid push_front?

[Qiang(Joe) Xu, 2016/07/07 00:32:45]

done. tks.

+  }
+}
+
+void AudioManagerCras::GetAudioInputDeviceNames(
+    AudioDeviceNames* device_names) {
+  mic_positions_ = ParsePointsFromString(MicPositions());
+  GetAudioDeviceNamesImpl(true, device_names);
 }
 
 void AudioManagerCras::GetAudioOutputDeviceNames(
     AudioDeviceNames* device_names) {
-  AddDefaultDevice(device_names);
+  GetAudioDeviceNamesImpl(false, device_names);
 }
 
 AudioParameters AudioManagerCras::GetInputStreamParameters(