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

content/common/media/audio_messages.h

 // 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.
 
 // IPC messages for the audio.
 // Multiply-included message file, hence no include guard.
 
 #include <stdint.h>
 
 #include <string>
 
 #include "base/memory/shared_memory.h"
 #include "base/sync_socket.h"
 #include "content/common/content_export.h"
 #include "ipc/ipc_message_macros.h"
 #include "media/audio/audio_input_ipc.h"
 #include "media/audio/audio_output_ipc.h"
 #include "media/base/ipc/media_param_traits.h"
 #include "media/gpu/ipc/common/media_param_traits.h"
 #include "url/origin.h"
 
 #undef IPC_MESSAGE_EXPORT
 #define IPC_MESSAGE_EXPORT CONTENT_EXPORT
 #define IPC_MESSAGE_START AudioMsgStart
 
 IPC_ENUM_TRAITS_MAX_VALUE(media::AudioInputIPCDelegateState,
                           media::AUDIO_INPUT_IPC_DELEGATE_STATE_LAST)
 
 IPC_ENUM_TRAITS_MAX_VALUE(media::OutputDeviceStatus,
-                          media::OUTPUT_DEVICE_STATUS_LAST)
+                          media::OUTPUT_DEVICE_STATUS_MAX)
 
 IPC_STRUCT_BEGIN(AudioInputHostMsg_CreateStream_Config)
   IPC_STRUCT_MEMBER(media::AudioParameters, params)
   IPC_STRUCT_MEMBER(bool, automatic_gain_control)
   IPC_STRUCT_MEMBER(uint32_t, shared_memory_count)
 IPC_STRUCT_END()
 
 // Messages sent from the browser to the renderer.
 
 // Tell the renderer process that an audio output device has been authorized
@@ skipping 91 matching lines @@
 // Set audio volume of the stream specified by stream_id.
 // TODO(hclam): change this to vector if we have channel numbers other than 2.
 IPC_MESSAGE_CONTROL2(AudioHostMsg_SetVolume,
                      int /* stream_id */,
                      double /* volume */)
 
 // Set audio volume of the input stream specified by stream_id.
 IPC_MESSAGE_CONTROL2(AudioInputHostMsg_SetVolume,
                      int /* stream_id */,
                      double /* volume */)