fallback to null sink in WebAudioSourceProvider::Initialize() + UMA stats for device status

media/base/output_device_info.h

 // Copyright 2016 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.
 
 #ifndef MEDIA_BASE_OUTPUT_DEVICE_INFO_H_
 #define MEDIA_BASE_OUTPUT_DEVICE_INFO_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "media/base/audio_parameters.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 // Result of an audio output device switch operation
 enum OutputDeviceStatus {
   OUTPUT_DEVICE_STATUS_OK = 0,
   OUTPUT_DEVICE_STATUS_ERROR_NOT_FOUND,
   OUTPUT_DEVICE_STATUS_ERROR_NOT_AUTHORIZED,
   OUTPUT_DEVICE_STATUS_ERROR_TIMED_OUT,
   OUTPUT_DEVICE_STATUS_ERROR_INTERNAL,
-  OUTPUT_DEVICE_STATUS_LAST = OUTPUT_DEVICE_STATUS_ERROR_INTERNAL,
+  // Add new values only above this line; do not changes existing values. Make
+  // sure OutputDeviceStatus enum in histoframs.xml is updated with any change
+  // here.
+  OUTPUT_DEVICE_STATUS_MAX = OUTPUT_DEVICE_STATUS_ERROR_INTERNAL
 };
 
 using OutputDeviceStatusCB = base::Callback<void(OutputDeviceStatus)>;
 
 // Output device information returned by
 // AudioRendererSink::GetOutputDeviceInfo()
 class MEDIA_EXPORT OutputDeviceInfo {
  public:
   // Use this constructor to initialize with "no info available" values.
   OutputDeviceInfo();
@@ skipping 28 matching lines @@
 
  private:
   std::string device_id_;
   OutputDeviceStatus device_status_;
   AudioParameters output_params_;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_OUTPUT_DEVICE_INFO_H_