Do not pass the string device_id via IPC message to create an audio input stream

content/browser/renderer_host/media/audio_input_device_manager_event_handler.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.
-
-// AudioInputDeviceManagerEventHandler is used to signal events from
-// AudioInoutDeviceManager when it's time to start and stop devices.
-
-#ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_DEVICE_MANAGER_EVENT_HANDLER_H_
-#define CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_DEVICE_MANAGER_EVENT_HANDLER_H_
-
-#include "content/common/content_export.h"
-
-namespace content {
-
-class CONTENT_EXPORT AudioInputDeviceManagerEventHandler {
- public:
-  // Called by AudioInputDeviceManager to create an audio stream using the
-  // device index when the device has been started.
-  virtual void OnDeviceStarted(int session_id,
-                               const std::string& device_id) = 0;
-
-  // Called by AudioInputDeviceManager to stop the audio stream when a device
-  // has been stopped. This method is used only when users call Close() without
-  // calling Stop() on a started device.
-  virtual void OnDeviceStopped(int session_id) = 0;
-
- protected:
-  virtual ~AudioInputDeviceManagerEventHandler() {}
-};
-
-}  // namespace content
-
-#endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_DEVICE_MANAGER_EVENT_HANDLER_H_