support video device enumeration from renderer process.

content/renderer/media/media_stream_impl_stub.cc

 // 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.
 
 #include "content/renderer/media/media_stream_impl.h"
 
 #include "content/renderer/media/media_stream_dependency_factory.h"
 #include "content/renderer/media/rtc_video_decoder.h"
 #include "content/renderer/media/video_capture_impl_manager.h"
 #include "content/renderer/p2p/ipc_socket_factory.h"
@@ skipping 61 matching lines @@
 void MediaStreamImpl::OnStreamGenerationFailed(int request_id) {
 }
 
 void MediaStreamImpl::OnVideoDeviceFailed(const std::string& label,
                                           int index) {
 }
 
 void MediaStreamImpl::OnAudioDeviceFailed(const std::string& label,
                                           int index) {
 }
+
+void MediaStreamImpl::OnDevicesEnumerated(
+    int request_id,
+    const media_stream::StreamDeviceInfoArray& device_array) {
+}
+
+void MediaStreamImpl::OnDevicesEnumerationFailed(int request_id) {
+}
+
+void MediaStreamImpl::OnDeviceOpened(
+    int request_id,
+    const std::string& label,
+    const media_stream::StreamDeviceInfo& video_device) {
+}
+
+void MediaStreamImpl::OnDeviceOpenFailed(int request_id) {
+}