Late initialize MediaController, for less resource i.e. ProcessThread, usage by PeerConnection.

webrtc/api/fakemediacontroller.h

Index: webrtc/api/fakemediacontroller.h
diff --git a/webrtc/api/fakemediacontroller.h b/webrtc/api/fakemediacontroller.h
index 2e539e813aa431f6538060a768a30bb132a45843..bc3f3e2fdd183afc449afd1d2241f3ff202338ae 100644
--- a/webrtc/api/fakemediacontroller.h
+++ b/webrtc/api/fakemediacontroller.h
@@ -26,6 +26,7 @@ class FakeMediaController : public webrtc::MediaControllerInterface {
     RTC_DCHECK(nullptr != call_);
   }
   ~FakeMediaController() override {}
+  void Close() override {}
   webrtc::Call* call_w() override { return call_; }
   cricket::ChannelManager* channel_manager() const override {
     return channel_manager_;