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

webrtc/api/peerconnection.h

Index: webrtc/api/peerconnection.h
diff --git a/webrtc/api/peerconnection.h b/webrtc/api/peerconnection.h
index a63dd4342358fc96b21a38fe3f67237ed7d98545..93bfe381ce1e244e9b5eb2bc2ed4e837b469520d 100644
--- a/webrtc/api/peerconnection.h
+++ b/webrtc/api/peerconnection.h
@@ -14,6 +14,7 @@
 #include <string>
 
 #include "webrtc/api/dtlsidentitystore.h"
+#include "webrtc/api/mediaconstraintsinterface.h"
 #include "webrtc/api/peerconnectionfactory.h"
 #include "webrtc/api/peerconnectioninterface.h"
 #include "webrtc/api/rtpreceiverinterface.h"
@@ -21,6 +22,7 @@
 #include "webrtc/api/statscollector.h"
 #include "webrtc/api/streamcollection.h"
 #include "webrtc/api/webrtcsession.h"
+#include "webrtc/base/constructormagic.h"
 #include "webrtc/base/scoped_ptr.h"
 
 namespace webrtc {
@@ -74,7 +76,8 @@ class PeerConnection : public PeerConnectionInterface,
       std::vector<MediaStreamInterface*> streams) override;
   bool RemoveTrack(RtpSenderInterface* sender) override;
 
-  virtual WebRtcSession* session() { return session_.get(); }
+  // This is virtual so it can be mocked.
+  virtual WebRtcSession* session();
 
   rtc::scoped_refptr<DtmfSenderInterface> CreateDtmfSender(
       AudioTrackInterface* track) override;
@@ -150,6 +153,9 @@ class PeerConnection : public PeerConnectionInterface,
   };
   typedef std::vector<TrackInfo> TrackInfos;
 
+  class StoredConstraints;
+  class LiveSession;
+
   // Implements MessageHandler.
   void OnMessage(rtc::Message* msg) override;
 
@@ -329,6 +335,12 @@ class PeerConnection : public PeerConnectionInterface,
   // or nullptr if not found.
   DataChannel* FindDataChannelBySid(int sid) const;
 
+  void CreateLiveSession();
+  void DestroyLiveSession();
+  const WebRtcSession* session() const;
+  RemoteMediaStreamFactory* remote_stream_factory();
+  StatsCollector* stats();
+
   // Storing the factory as a scoped reference pointer ensures that the memory
   // in the PeerConnectionFactoryImpl remains available as long as the
   // PeerConnection is running. It is passed to PeerConnection as a raw pointer.
@@ -345,7 +357,6 @@ class PeerConnection : public PeerConnectionInterface,
   IceGatheringState ice_gathering_state_;
 
   rtc::scoped_ptr<cricket::PortAllocator> port_allocator_;
-  rtc::scoped_ptr<MediaControllerInterface> media_controller_;
 
   // Streams added via AddStream.
   rtc::scoped_refptr<StreamCollection> local_streams_;
@@ -367,17 +378,21 @@ class PeerConnection : public PeerConnectionInterface,
   std::vector<rtc::scoped_refptr<DataChannel>> sctp_data_channels_to_free_;
 
   bool remote_peer_supports_msid_ = false;
-  rtc::scoped_ptr<RemoteMediaStreamFactory> remote_stream_factory_;
 
   std::vector<rtc::scoped_refptr<RtpSenderInterface>> senders_;
   std::vector<rtc::scoped_refptr<RtpReceiverInterface>> receivers_;
 
-  // The session_ scoped_ptr is declared at the bottom of PeerConnection
+  cricket::MediaConfig media_config_;
+  PeerConnectionInterface::RTCConfiguration configuration_;
+  rtc::scoped_ptr<StoredConstraints> constraints_;
+  rtc::scoped_ptr<DtlsIdentityStoreInterface> dtls_identity_store_;
+
+  // The live_session_ scoped_ptr is declared at the bottom of PeerConnection
   // because its destruction fires signals (such as VoiceChannelDestroyed)
   // which will trigger some final actions in PeerConnection...
-  rtc::scoped_ptr<WebRtcSession> session_;
-  // ... But stats_ depends on session_ so it should be destroyed even earlier.
-  rtc::scoped_ptr<StatsCollector> stats_;
+  rtc::scoped_ptr<LiveSession> live_session_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(PeerConnection);
 };
 
 }  // namespace webrtc