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

webrtc/api/webrtcsession_unittest.cc

Index: webrtc/api/webrtcsession_unittest.cc
diff --git a/webrtc/api/webrtcsession_unittest.cc b/webrtc/api/webrtcsession_unittest.cc
index 16ce621eb81d5e5c26cae467708a33cf49fadc23..2ddd2571e2cd183ec4077c47bc332962eb284e2c 100644
--- a/webrtc/api/webrtcsession_unittest.cc
+++ b/webrtc/api/webrtcsession_unittest.cc
@@ -202,13 +202,11 @@ class MockIceObserver : public webrtc::IceObserver {
 
 class WebRtcSessionForTest : public webrtc::WebRtcSession {
  public:
-  WebRtcSessionForTest(webrtc::MediaControllerInterface* media_controller,
-                       rtc::Thread* signaling_thread,
+  WebRtcSessionForTest(rtc::Thread* signaling_thread,
                        rtc::Thread* worker_thread,
                        cricket::PortAllocator* port_allocator,
                        webrtc::IceObserver* ice_observer)
-      : WebRtcSession(media_controller,
-                      signaling_thread,
+      : WebRtcSession(signaling_thread,
                       worker_thread,
                       port_allocator) {
     RegisterIceObserver(ice_observer);
@@ -373,8 +371,8 @@ class WebRtcSessionTest
       const PeerConnectionInterface::RTCConfiguration& rtc_configuration) {
     ASSERT_TRUE(session_.get() == NULL);
     session_.reset(new WebRtcSessionForTest(
-        media_controller_.get(), rtc::Thread::Current(), rtc::Thread::Current(),
-        allocator_.get(), &observer_));
+        rtc::Thread::Current(), rtc::Thread::Current(), allocator_.get(),
+        &observer_));
     session_->SignalDataChannelOpenMessage.connect(
         this, &WebRtcSessionTest::OnDataChannelOpenMessage);
     session_->GetOnDestroyedSignal()->connect(
@@ -388,6 +386,7 @@ class WebRtcSessionTest
     EXPECT_TRUE(session_->Initialize(options_, constraints_.get(),
                                      std::move(dtls_identity_store),
                                      rtc_configuration));
+    session_->LateInitialize(media_controller_.get());
     session_->set_metrics_observer(metrics_observer_);
   }