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

webrtc/modules/audio_device/linux/audio_device_pulse_linux.h

 /*
  *  Copyright (c) 2012 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.
  */
 
@@ skipping 85 matching lines @@
 {
 public:
     AudioDeviceLinuxPulse(const int32_t id);
     virtual ~AudioDeviceLinuxPulse();
 
     // Retrieve the currently utilized audio layer
     int32_t ActiveAudioLayer(
         AudioDeviceModule::AudioLayer& audioLayer) const override;
 
     // Main initializaton and termination
-    int32_t Init() override;
+    InitStatus Init() override;
     int32_t Terminate() override;
     bool Initialized() const override;
 
     // Device enumeration
     int16_t PlayoutDevices() override;
     int16_t RecordingDevices() override;
     int32_t PlayoutDeviceName(uint16_t index,
                               char name[kAdmMaxDeviceNameSize],
                               char guid[kAdmMaxGuidSize]) override;
     int32_t RecordingDeviceName(uint16_t index,
@@ skipping 252 matching lines @@
     pa_buffer_attr _playBufferAttr;
     pa_buffer_attr _recBufferAttr;
 
     char _oldKeyState[32];
     Display* _XDisplay;
 };
 
 }
 
 #endif  // MODULES_AUDIO_DEVICE_MAIN_SOURCE_LINUX_AUDIO_DEVICE_PULSE_LINUX_H_