Implement GetAudioOutputDeviceNames for Mac OS X.

media/audio/mac/audio_manager_mac.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/mac/audio_manager_mac.h"
 
 #include <CoreAudio/AudioHardware.h>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 63 matching lines @@
 // Returns true if the default input device is the same as
 // the default output device.
 bool AudioManagerMac::HasUnifiedDefaultIO() {
   AudioDeviceID input_id, output_id;
   if (!GetDefaultInputDevice(&input_id) || !GetDefaultOutputDevice(&output_id))
     return false;
 
   return input_id == output_id;
 }
 
+// Retrieves information on audio devices, and prepends the default
+// device to the list if the list is non-empty.
 static void GetAudioDeviceInfo(bool is_input,
                                media::AudioDeviceNames* device_names) {
   // Query the number of total devices.
   AudioObjectPropertyAddress property_address = {
     kAudioHardwarePropertyDevices,
     kAudioObjectPropertyScopeGlobal,
     kAudioObjectPropertyElementMaster
   };
   UInt32 size = 0;
   OSStatus result = AudioObjectGetPropertyDataSize(kAudioObjectSystemObject,
@@ skipping 72 matching lines @@
     device_names->push_back(device_name);
 
     // We are responsible for releasing the returned CFObject.  See the
     // comment in the AudioHardware.h for constant
     // kAudioDevicePropertyDeviceUID.
     if (uid)
       CFRelease(uid);
     if (name)
       CFRelease(name);
   }
+
+  if (!device_names->empty()) {
+    // Prepend the default device to the list since we always want it to be
+    // on the top of the list for all platforms. There is no duplicate
+    // counting here since the default device has been abstracted out before.
+    media::AudioDeviceName name;
+    name.device_name = AudioManagerBase::kDefaultDeviceName;
+    name.unique_id =  AudioManagerBase::kDefaultDeviceId;

[tommi (sloooow) - chröme, 2013/09/09 16:09:23]

nit: one space after =

[Jói, 2013/09/09 16:15:44]

Done.

+    device_names->push_front(name);
+  }
 }
 
 static AudioDeviceID GetAudioDeviceIdByUId(bool is_input,
                                            const std::string& device_id) {
   AudioObjectPropertyAddress property_address = {
     kAudioHardwarePropertyDevices,
     kAudioObjectPropertyScopeGlobal,
     kAudioObjectPropertyElementMaster
   };
   AudioDeviceID audio_device_id = kAudioObjectUnknown;
@@ skipping 203 matching lines @@
   if (!GetDefaultOutputDevice(&device_id))
     return kFallbackSampleRate;
 
   return HardwareSampleRateForDevice(device_id);
 }
 
 void AudioManagerMac::GetAudioInputDeviceNames(
     media::AudioDeviceNames* device_names) {
   DCHECK(device_names->empty());
   GetAudioDeviceInfo(true, device_names);
-  if (!device_names->empty()) {
-    // Prepend the default device to the list since we always want it to be
-    // on the top of the list for all platforms. There is no duplicate
-    // counting here since the default device has been abstracted out before.
-    media::AudioDeviceName name;
-    name.device_name = AudioManagerBase::kDefaultDeviceName;
-    name.unique_id =  AudioManagerBase::kDefaultDeviceId;
-    device_names->push_front(name);
-  }
+}
+
+void AudioManagerMac::GetAudioOutputDeviceNames(
+    media::AudioDeviceNames* device_names) {
+  DCHECK(device_names->empty());
+  GetAudioDeviceInfo(false, device_names);
 }
 
 AudioParameters AudioManagerMac::GetInputStreamParameters(
     const std::string& device_id) {
   // Due to the sharing of the input and output buffer sizes, we need to choose
   // the input buffer size based on the output sample rate.  See
   // http://crbug.com/154352.
   const int buffer_size = ChooseBufferSize(
       AUAudioOutputStream::HardwareSampleRate());
 
@@ skipping 187 matching lines @@
   current_sample_rate_ = new_sample_rate;
   current_output_device_ = new_output_device;
   NotifyAllOutputDeviceChangeListeners();
 }
 
 AudioManager* CreateAudioManager() {
   return new AudioManagerMac();
 }
 
 }  // namespace media