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

webrtc/modules/audio_device/dummy/file_audio_device.cc

 /*
  *  Copyright (c) 2014 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/base/platform_thread.h"
@@ skipping 37 matching lines @@
 FileAudioDevice::~FileAudioDevice() {
   delete &_outputFile;
   delete &_inputFile;
 }
 
 int32_t FileAudioDevice::ActiveAudioLayer(
     AudioDeviceModule::AudioLayer& audioLayer) const {
   return -1;
 }
 
-int32_t FileAudioDevice::Init() { return 0; }
+AudioDeviceGeneric::InitStatus FileAudioDevice::Init() {
+  return InitStatus::OK;
+}
 
 int32_t FileAudioDevice::Terminate() { return 0; }
 
 bool FileAudioDevice::Initialized() const { return true; }
 
 int16_t FileAudioDevice::PlayoutDevices() {
   return 1;
 }
 
 int16_t FileAudioDevice::RecordingDevices() {
@@ skipping 455 matching lines @@
 
     uint64_t deltaTimeMillis = _clock->CurrentNtpInMilliseconds() - currentTime;
     if(deltaTimeMillis < 10) {
       SleepMs(10 - deltaTimeMillis);
     }
 
     return true;
 }
 
 }  // namespace webrtc