UMA log for audio_device Init and Start(Playout|Recording). Make Init return a more specific error …

webrtc/modules/audio_device/dummy/audio_device_dummy.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/modules/audio_device/dummy/audio_device_dummy.h"
 
 namespace webrtc {
 
 int32_t AudioDeviceDummy::ActiveAudioLayer(
     AudioDeviceModule::AudioLayer& audioLayer) const {
   return -1;
 }
 
-int32_t AudioDeviceDummy::Init() { return 0; }
+AudioDeviceGeneric::InitStatus AudioDeviceDummy::Init() {
+  return InitStatus::OK;
+}
 
 int32_t AudioDeviceDummy::Terminate() { return 0; }
 
 bool AudioDeviceDummy::Initialized() const { return true; }
 
 int16_t AudioDeviceDummy::PlayoutDevices() { return -1; }
 
 int16_t AudioDeviceDummy::RecordingDevices() { return -1; }
 
 int32_t AudioDeviceDummy::PlayoutDeviceName(uint16_t index,
@@ skipping 175 matching lines @@
 void AudioDeviceDummy::ClearPlayoutWarning() {}
 
 void AudioDeviceDummy::ClearPlayoutError() {}
 
 void AudioDeviceDummy::ClearRecordingWarning() {}
 
 void AudioDeviceDummy::ClearRecordingError() {}
 
 void AudioDeviceDummy::AttachAudioBuffer(AudioDeviceBuffer* audioBuffer) {}
 }  // namespace webrtc