Add dummy implementation to MockVideoSource.

content/renderer/media/webrtc/mock_peer_connection_dependency_factory.cc

Index: content/renderer/media/webrtc/mock_peer_connection_dependency_factory.cc
diff --git a/content/renderer/media/webrtc/mock_peer_connection_dependency_factory.cc b/content/renderer/media/webrtc/mock_peer_connection_dependency_factory.cc
index ca3f29851a3c031b9a21e88867d6e84f155ba292..27027866d0607243baa988641fc7a303c9758a97 100644
--- a/content/renderer/media/webrtc/mock_peer_connection_dependency_factory.cc
+++ b/content/renderer/media/webrtc/mock_peer_connection_dependency_factory.cc
@@ -218,6 +218,13 @@ void MockVideoSource::RemoveSink(cricket::VideoRenderer* output) {
   NOTIMPLEMENTED();
 }
 
+void MockVideoSource::Stop() {
+  NOTIMPLEMENTED();
+}
+void MockVideoSource::Restart() {
+  NOTIMPLEMENTED();
+}
+
 cricket::VideoRenderer* MockVideoSource::FrameInput() {
   return &renderer_;
 }