Moving creation of sessiondescriptions to webrtcsession.

Fixing defect durin close down in peerconnectionmanager.

BUG=
TEST=

Review URL: http://webrtc-codereview.appspot.com/193004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@693 4adac7df-926f-26a2-2b94-8c16560cd09d

15 files changed, 355 insertions, 176 deletions

diff --git a/third_party_mods/libjingle/libjingle.gyp b/third_party_mods/libjingle/libjingle.gyp
index 54d7a0f68c..ea537b7938 100644
--- a/third_party_mods/libjingle/libjingle.gyp
+++ b/third_party_mods/libjingle/libjingle.gyp
@@ -702,6 +702,7 @@
             '<(libjingle_mods)/source/talk/app/webrtc_dev/peerconnectionsignaling.cc',
             '<(libjingle_mods)/source/talk/app/webrtc_dev/peerconnectionsignaling.h',
             '<(libjingle_mods)/source/talk/app/webrtc_dev/ref_count.h',
+            '<(libjingle_mods)/source/talk/app/webrtc_dev/sessiondescriptionprovider.h'
             '<(libjingle_mods)/source/talk/app/webrtc_dev/streamcollectionimpl.h',            
             '<(libjingle_mods)/source/talk/app/webrtc_dev/videorendererimpl.cc',
             '<(libjingle_mods)/source/talk/app/webrtc_dev/videotrackimpl.cc',
@@ -710,6 +711,7 @@
             '<(libjingle_mods)/source/talk/app/webrtc_dev/webrtc_devicemanager.cc',
             '<(libjingle_mods)/source/talk/app/webrtc_dev/webrtcjson.cc',
             '<(libjingle_mods)/source/talk/app/webrtc_dev/webrtcjson.h',
+            '<(libjingle_mods)/source/talk/app/webrtc_dev/webrtcsessionobserver',
             '<(libjingle_mods)/source/talk/app/webrtc_dev/webrtcsession.cc',
             '<(libjingle_mods)/source/talk/app/webrtc_dev/webrtcsession.h',
           ],
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionimpl.cc b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionimpl.cc
index 64b04055ed..5b5a98c713 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionimpl.cc
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionimpl.cc
@@ -60,7 +60,8 @@ enum ServiceType {
 enum {
     MSG_COMMITSTREAMCHANGES = 1,
     MSG_PROCESSSIGNALINGMESSAGE = 2,
-    MSG_RETURNREMOTEMEDIASTREAMS = 3
+    MSG_RETURNREMOTEMEDIASTREAMS = 3,
+    MSG_TERMINATE = 4
 };
 
 bool static ParseConfigString(const std::string& config,
@@ -137,10 +138,10 @@ PeerConnectionImpl::PeerConnectionImpl(
           network_manager->network_manager(),
           socket_factory->socket_factory(),
           std::string(kUserAgent))),
-      signaling_(new PeerConnectionSignaling(channel_manager,
-                                             signaling_thread)),
       session_(new WebRtcSession(channel_manager, signaling_thread,
-          worker_thread, port_allocator_.get(), signaling_.get())),
+          worker_thread, port_allocator_.get())),
+      signaling_(new PeerConnectionSignaling(signaling_thread,
+                                             session_.get())),
       stream_handler_(new MediaStreamHandlers(session_.get())) {
   signaling_->SignalNewPeerConnectionMessage.connect(
       this, &PeerConnectionImpl::OnNewPeerConnectionMessage);
@@ -152,6 +153,15 @@ PeerConnectionImpl::PeerConnectionImpl(
 
 PeerConnectionImpl::~PeerConnectionImpl() {
   signaling_thread_->Clear(this);
+  signaling_thread_->Send(this, MSG_TERMINATE);
+}
+
+// Clean up what needs to be cleaned up on the signaling thread.
+void PeerConnectionImpl::Terminate_s() {
+  stream_handler_.reset();
+  signaling_.reset();
+  session_.reset();
+  port_allocator_.reset();
 }
 
 bool PeerConnectionImpl::Initialize(const std::string& configuration,
@@ -182,6 +192,7 @@ bool PeerConnectionImpl::Initialize(const std::string& configuration,
       ASSERT(!"NOT SUPPORTED");
       return false;
   }
+
   // Initialize the WebRtcSession. It creates transport channels etc.
   return session_->Initialize();
 }
@@ -241,6 +252,10 @@ void PeerConnectionImpl::OnMessage(talk_base::Message* msg) {
       param->data() = StreamCollectionImpl::Create(remote_media_streams_);
       break;
     }
+    case MSG_TERMINATE: {
+      Terminate_s();
+      break;
+    }
   }
 }
 
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionimpl.h b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionimpl.h
index 46e9b131fa..c7c7c2c479 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionimpl.h
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionimpl.h
@@ -84,6 +84,8 @@ class PeerConnectionImpl : public PeerConnection,
   void OnRemoteStreamAdded(MediaStream* remote_stream);
   void OnRemoteStreamRemoved(MediaStream* remote_stream);
 
+  void Terminate_s();
+
   PeerConnectionObserver* observer_;
   scoped_refptr<StreamCollectionImpl> local_media_streams_;
   scoped_refptr<StreamCollectionImpl> remote_media_streams_;
@@ -93,8 +95,8 @@ class PeerConnectionImpl : public PeerConnection,
   scoped_refptr<PcNetworkManager> network_manager_;
   scoped_refptr<PcPacketSocketFactory> socket_factory_;
   talk_base::scoped_ptr<cricket::HttpPortAllocator> port_allocator_;
-  talk_base::scoped_ptr<PeerConnectionSignaling> signaling_;
   talk_base::scoped_ptr<WebRtcSession> session_;
+  talk_base::scoped_ptr<PeerConnectionSignaling> signaling_;
   talk_base::scoped_ptr<MediaStreamHandlers> stream_handler_;
 };
 
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmanagerimpl.cc b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmanagerimpl.cc
index f8044bdbff..68b6c3f34f 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmanagerimpl.cc
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmanagerimpl.cc
@@ -165,7 +165,7 @@ PeerConnectionManagerImpl::~PeerConnectionManagerImpl() {
 
 bool PeerConnectionManagerImpl::Initialize() {
   InitMessageData result(false);
-  signaling_thread_->Send(this, MSG_INIT_MANAGER, &result);
+  signaling_thread_ptr_->Send(this, MSG_INIT_MANAGER, &result);
   return result.data();
 }
 
@@ -214,7 +214,7 @@ scoped_refptr<PeerConnection> PeerConnectionManagerImpl::CreatePeerConnection(
     const std::string& configuration,
     PeerConnectionObserver* observer) {
   CreatePeerConnectionParams params(configuration, observer);
-  signaling_thread_->Send(this, MSG_CREATE_PEERCONNECTION, &params);
+  signaling_thread_ptr_->Send(this, MSG_CREATE_PEERCONNECTION, &params);
   return params.peerconnection;
 }
 
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage.cc b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage.cc
index 9dc54be1a0..93276d050f 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage.cc
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage.cc
@@ -34,30 +34,29 @@
 
 namespace webrtc {
 
-scoped_refptr<PeerConnectionMessage> PeerConnectionMessage::Create(
+PeerConnectionMessage* PeerConnectionMessage::Create(
     PeerConnectionMessageType type,
-    cricket::SessionDescription* desc,
+    const cricket::SessionDescription* desc,
     const std::vector<cricket::Candidate>& candidates) {
-  return new RefCountImpl<PeerConnectionMessage> (type, desc, candidates);
+  return new PeerConnectionMessage(type, desc, candidates);
 }
 
-scoped_refptr<PeerConnectionMessage> PeerConnectionMessage::Create(
+PeerConnectionMessage* PeerConnectionMessage::Create(
     const std::string& message) {
-  scoped_refptr<PeerConnectionMessage>pc_message(new
-      RefCountImpl<PeerConnectionMessage> ());
+  PeerConnectionMessage* pc_message(new PeerConnectionMessage());
   if (!pc_message->Deserialize(message))
     return NULL;
   return pc_message;
 }
 
-scoped_refptr<PeerConnectionMessage> PeerConnectionMessage::CreateErrorMessage(
+PeerConnectionMessage* PeerConnectionMessage::CreateErrorMessage(
     ErrorCode error) {
-  return new RefCountImpl<PeerConnectionMessage> (error);
+  return new PeerConnectionMessage(error);
 }
 
 PeerConnectionMessage::PeerConnectionMessage(
     PeerConnectionMessageType type,
-    cricket::SessionDescription* desc,
+    const cricket::SessionDescription* desc,
     const std::vector<cricket::Candidate>& candidates)
     : type_(type),
       error_code_(kNoError),
@@ -68,7 +67,7 @@ PeerConnectionMessage::PeerConnectionMessage(
 PeerConnectionMessage::PeerConnectionMessage()
     : type_(kOffer),
       error_code_(kNoError),
-      desc_(new cricket::SessionDescription()) {
+      desc_(NULL) {
 }
 
 PeerConnectionMessage::PeerConnectionMessage(ErrorCode error)
@@ -78,12 +77,19 @@ PeerConnectionMessage::PeerConnectionMessage(ErrorCode error)
 }
 
 std::string PeerConnectionMessage::Serialize() {
-  return JsonSerialize(type_, error_code_, desc_.get(), candidates_);
+  return JsonSerialize(type_, error_code_, desc_, candidates_);
 }
 
 bool PeerConnectionMessage::Deserialize(std::string message) {
-  return JsonDeserialize(&type_, &error_code_, desc_.get(),
-      &candidates_, message);
+  cricket::SessionDescription* desc(new cricket::SessionDescription());
+  bool result = JsonDeserialize(&type_, &error_code_, desc,
+                                &candidates_, message);
+  if(!result) {
+    delete desc;
+    desc = NULL;
+  }
+  desc_ = desc;
+  return result;
 }
 
 }  // namespace webrtc
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage.h b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage.h
index 5a23a8f62a..12fc7607e4 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage.h
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage.h
@@ -46,8 +46,8 @@ namespace webrtc {
 // PeerConnectionMessage represent an SDP offer or an answer.
 // Instances of this class can be serialized / deserialized and are used for
 // signaling between PeerConnection objects.
-// Each instance has a type, a sequence number and a session description.
-class PeerConnectionMessage : public RefCount {
+// Each instance has a type and a session description.
+class PeerConnectionMessage {
  public:
   enum PeerConnectionMessageType {
     kOffer,
@@ -63,37 +63,37 @@ class PeerConnectionMessage : public RefCount {
     kMessageNotDeliverable = 40  // The signaling channel is broken.
   };
 
-  static scoped_refptr<PeerConnectionMessage> Create(
+  static PeerConnectionMessage* Create(
       PeerConnectionMessageType type,
-      cricket::SessionDescription* desc,
+      const cricket::SessionDescription* desc,
       const std::vector<cricket::Candidate>& candidates);
 
-  static scoped_refptr<PeerConnectionMessage> Create(
+  static PeerConnectionMessage* Create(
       const std::string& message);
 
-  static scoped_refptr<PeerConnectionMessage> CreateErrorMessage(
+  static PeerConnectionMessage* CreateErrorMessage(
       ErrorCode error);
 
   PeerConnectionMessageType type() {return type_;}
   ErrorCode error() {return error_code_;}
-  const cricket::SessionDescription* desc() {return desc_.get();}
+  const cricket::SessionDescription* desc() {return desc_;}
 
   std::string Serialize();
   std::vector<cricket::Candidate>& candidates() { return candidates_; }
 
  protected:
   PeerConnectionMessage(PeerConnectionMessageType type,
-                        cricket::SessionDescription* desc,
+                        const cricket::SessionDescription* desc,
                         const std::vector<cricket::Candidate>& candidates);
-  PeerConnectionMessage();
   explicit PeerConnectionMessage(ErrorCode error);
+  PeerConnectionMessage();
 
   bool Deserialize(std::string message);
 
  private:
   PeerConnectionMessageType type_;
   ErrorCode error_code_;
-  talk_base::scoped_ptr<cricket::SessionDescription> desc_;
+  const cricket::SessionDescription* desc_;  // Weak ref.
   std::vector<cricket::Candidate> candidates_;
 };
 
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage_unittest.cc b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage_unittest.cc
index ec2d116b4e..0bc341b22a 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage_unittest.cc
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionmessage_unittest.cc
@@ -101,27 +101,27 @@ class PeerConnectionMessageTest: public testing::Test {
 
 TEST_F(PeerConnectionMessageTest, Serialize) {
   std::string message;
-  scoped_refptr<PeerConnectionMessage> pc_message;
+  talk_base::scoped_ptr<PeerConnectionMessage> pc_message;
 
   // Offer
-  cricket::SessionDescription* offer =
-      session_description_factory_->CreateOffer(options_);
-  pc_message = PeerConnectionMessage::Create(PeerConnectionMessage::kOffer,
-      offer, candidates_);
+  talk_base::scoped_ptr<const cricket::SessionDescription> offer(
+      session_description_factory_->CreateOffer(options_));
+  pc_message.reset(PeerConnectionMessage::Create(PeerConnectionMessage::kOffer,
+      offer.get(), candidates_));
   message = pc_message->Serialize();
   LOG(LS_INFO) << message;
 
   // Answer
-  cricket::SessionDescription* answer =
-      session_description_factory_->CreateAnswer(offer, options_);
-  pc_message = PeerConnectionMessage::Create(PeerConnectionMessage::kAnswer,
-      answer, candidates_);
+  talk_base::scoped_ptr<const cricket::SessionDescription> answer(
+      session_description_factory_->CreateAnswer(offer.get(), options_));
+  pc_message.reset(PeerConnectionMessage::Create(PeerConnectionMessage::kAnswer,
+      answer.get(), candidates_));
   message = pc_message->Serialize();
   LOG(LS_INFO) << message;
 
   // Error
-  pc_message = PeerConnectionMessage::CreateErrorMessage(
-      PeerConnectionMessage::kParseError);
+  pc_message.reset(PeerConnectionMessage::CreateErrorMessage(
+      PeerConnectionMessage::kParseError));
   message = pc_message->Serialize();
   LOG(LS_INFO) << message;
 
@@ -131,44 +131,44 @@ TEST_F(PeerConnectionMessageTest, Serialize) {
 TEST_F(PeerConnectionMessageTest, Deserialize) {
   std::string message_ref;
   std::string message_result;
-  scoped_refptr<PeerConnectionMessage> pc_message;
-  cricket::SessionDescription* offer =
-      session_description_factory_->CreateOffer(options_);
-  cricket::SessionDescription* answer =
-      session_description_factory_->CreateAnswer(offer, options_);
+  talk_base::scoped_ptr<PeerConnectionMessage> pc_message;
+  talk_base::scoped_ptr<cricket::SessionDescription> offer(
+      session_description_factory_->CreateOffer(options_));
+  talk_base::scoped_ptr<cricket::SessionDescription> answer(
+      session_description_factory_->CreateAnswer(offer.get(), options_));
 
   // Offer
-  pc_message = PeerConnectionMessage::Create(PeerConnectionMessage::kOffer,
-      offer, candidates_);
+  pc_message.reset(PeerConnectionMessage::Create(PeerConnectionMessage::kOffer,
+      offer.get(), candidates_));
   message_ref = pc_message->Serialize();
   LOG(LS_INFO) << "The reference message: " << message_ref;
 
   // Deserialize Offer
-  pc_message = PeerConnectionMessage::Create(message_ref);
+  pc_message.reset(PeerConnectionMessage::Create(message_ref));
   message_result = pc_message->Serialize();
   LOG(LS_INFO) << "The result message: " << message_result;
   EXPECT_EQ(message_ref, message_result);
 
   // Answer
-  pc_message = PeerConnectionMessage::Create(PeerConnectionMessage::kAnswer,
-      answer, candidates_);
+  pc_message.reset(PeerConnectionMessage::Create(PeerConnectionMessage::kAnswer,
+      answer.get(), candidates_));
   message_ref = pc_message->Serialize();
   LOG(LS_INFO) << "The reference message: " << message_ref;
 
   // Deserialize Answer
-  pc_message = PeerConnectionMessage::Create(message_ref);
+  pc_message.reset(PeerConnectionMessage::Create(message_ref));
   message_result = pc_message->Serialize();
   LOG(LS_INFO) << "The result message: " << message_result;
   EXPECT_EQ(message_ref, message_result);
 
   // Error
-  pc_message = PeerConnectionMessage::CreateErrorMessage(
-      PeerConnectionMessage::kParseError);
+  pc_message.reset(PeerConnectionMessage::CreateErrorMessage(
+      PeerConnectionMessage::kParseError));
   message_ref = pc_message->Serialize();
   LOG(LS_INFO) << "The reference message: " << message_ref;
 
   // Deserialize Error
-  pc_message = PeerConnectionMessage::Create(message_ref);
+  pc_message.reset(PeerConnectionMessage::Create(message_ref));
   message_result = pc_message->Serialize();
   LOG(LS_INFO) << "The result message: " << message_result;
   EXPECT_EQ(message_ref, message_result);
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling.cc b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling.cc
index 6c842d03b6..ecccbff39c 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling.cc
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling.cc
@@ -32,6 +32,7 @@
 #include "talk/app/webrtc_dev/audiotrackimpl.h"
 #include "talk/app/webrtc_dev/mediastreamimpl.h"
 #include "talk/app/webrtc_dev/videotrackimpl.h"
+#include "talk/app/webrtc_dev/sessiondescriptionprovider.h"
 #include "talk/base/helpers.h"
 #include "talk/base/messagequeue.h"
 #include "talk/session/phone/channelmanager.h"
@@ -74,18 +75,30 @@ static bool VerifyAnswer(const cricket::SessionDescription* answer_desc) {
 }
 
 PeerConnectionSignaling::PeerConnectionSignaling(
-    cricket::ChannelManager* channel_manager,
-    talk_base::Thread* signaling_thread)
+    talk_base::Thread* signaling_thread,
+    SessionDescriptionProvider* provider)
     : signaling_thread_(signaling_thread),
+      provider_(provider),
       state_(kInitializing),
-      ssrc_counter_(0),
-      session_description_factory_(channel_manager) {
+      ssrc_counter_(0) {
 }
 
 PeerConnectionSignaling::~PeerConnectionSignaling() {
+  // Cleanup the queued_received_offer_ if this object is
+  // deleted before the offer can be processed.
+  // That means we have parsed an offer and created the remote
+  // session description but we have not transfered the ownership
+  // to the provider yet.
+  if (queued_received_offer_.first) {
+    const cricket::SessionDescription* remote_desc =
+        queued_received_offer_.first->desc();
+    delete remote_desc;
+    delete queued_received_offer_.first;
+  }
+
 }
 
-void PeerConnectionSignaling::Initialize(
+void PeerConnectionSignaling::OnCandidatesReady(
     const cricket::Candidates& candidates) {
   ASSERT(state_ == kInitializing);
   if (state_ != kInitializing)
@@ -110,18 +123,18 @@ void PeerConnectionSignaling::ProcessSignalingMessage(
     StreamCollection* local_streams) {
   ASSERT(talk_base::Thread::Current() == signaling_thread_);
 
-  scoped_refptr<PeerConnectionMessage> signaling_message =
-      PeerConnectionMessage::Create(message);
+  talk_base::scoped_ptr<PeerConnectionMessage> signaling_message(
+      PeerConnectionMessage::Create(message));
   if (!signaling_message.get()) {
-    signaling_message = PeerConnectionMessage::CreateErrorMessage(
-        PeerConnectionMessage::kParseError);
+    signaling_message.reset(PeerConnectionMessage::CreateErrorMessage(
+        PeerConnectionMessage::kParseError));
     SignalNewPeerConnectionMessage(signaling_message->Serialize());
   }
 
   switch (signaling_message->type()) {
     case PeerConnectionMessage::kOffer: {
       queued_received_offer_ =
-          RemoteOfferPair(signaling_message, local_streams);
+          RemoteOfferPair(signaling_message.release(), local_streams);
       // If we are still Initializing we need to wait before we can handle
        // the offer. Queue it and handle it when the state change.
       if (state_ == kInitializing) {
@@ -135,9 +148,9 @@ void PeerConnectionSignaling::ProcessSignalingMessage(
             talk_base::CreateRandomId() % kGlareWaitIntervall;
         signaling_thread_->PostDelayed(
             timeout, this, MSG_SEND_QUEUED_OFFER, NULL);
-        scoped_refptr<PeerConnectionMessage> msg =
+        talk_base::scoped_ptr<PeerConnectionMessage> msg(
             PeerConnectionMessage::CreateErrorMessage(
-                PeerConnectionMessage::kWrongState);
+                PeerConnectionMessage::kWrongState));
         SignalNewPeerConnectionMessage(msg->Serialize());
         break;
       }
@@ -153,14 +166,15 @@ void PeerConnectionSignaling::ProcessSignalingMessage(
       ASSERT(state_ != PeerConnectionSignaling::kIdle);
       if (state_ == PeerConnectionSignaling::kIdle)
         return;
-      // Signal the resulting local and remote session description.
-      SignalUpdateSessionDescription(last_send_offer_->desc(),
-                                     signaling_message->desc(),
-                                     signaling_message->candidates());
-      UpdateRemoteStreams(signaling_message->desc());
+      const cricket::SessionDescription* remote_desc =
+          provider_->SetRemoteSessionDescription(
+              signaling_message->desc(),
+              signaling_message->candidates());
+      provider_->NegotiationDone();
+      UpdateRemoteStreams(remote_desc);
       scoped_refptr<StreamCollection> streams(queued_offers_.front());
       queued_offers_.pop_front();
-      UpdateSendingLocalStreams(signaling_message->desc(), streams);
+      UpdateSendingLocalStreams(remote_desc, streams);
       // Check if we have more offers waiting in the queue.
       if (queued_offers_.size() > 0) {
         // Send the next offer.
@@ -212,18 +226,13 @@ void PeerConnectionSignaling::CreateOffer_s() {
   cricket::MediaSessionOptions options;
   InitMediaSessionOptions(&options, local_streams);
 
-  talk_base::scoped_ptr<cricket::SessionDescription> offer(
-      session_description_factory_.CreateOffer(options));
+  const cricket::SessionDescription* local_desc =
+      provider_->ProvideOffer(options);
 
-  scoped_refptr<PeerConnectionMessage> offer_message =
+  talk_base::scoped_ptr<PeerConnectionMessage> offer_message(
       PeerConnectionMessage::Create(PeerConnectionMessage::kOffer,
-                                    offer.release(),
-                                    candidates_);
-
-  // If we are updating with new streams we need to get an answer
-  // before we can handle a remote offer.
-  // We also need the response before we are allowed to start send media.
-  last_send_offer_ = offer_message;
+                                    local_desc,
+                                    candidates_));
   SignalNewPeerConnectionMessage(offer_message->Serialize());
 }
 
@@ -232,8 +241,9 @@ PeerConnectionSignaling::State PeerConnectionSignaling::GetState() {
 }
 
 void PeerConnectionSignaling::CreateAnswer_s() {
-  scoped_refptr<PeerConnectionMessage> message(
-      queued_received_offer_.first.release());
+  talk_base::scoped_ptr<PeerConnectionMessage> message(
+      queued_received_offer_.first);
+  queued_received_offer_.first = NULL;
   scoped_refptr<StreamCollection> local_streams(
       queued_received_offer_.second.release());
 
@@ -241,37 +251,40 @@ void PeerConnectionSignaling::CreateAnswer_s() {
   signaling_thread_->Clear(this, MSG_SEND_QUEUED_OFFER, NULL);
   queued_offers_.clear();
 
+  // Let the provider know about the remote offer.
+  // The provider takes ownership and return a pointer for us to use.
+  const cricket::SessionDescription* remote_desc =
+      provider_->SetRemoteSessionDescription(message->desc(),
+                                             message->candidates());
+
   // Create a MediaSessionOptions object with the sources we want to send.
   cricket::MediaSessionOptions options;
   InitMediaSessionOptions(&options, local_streams);
+  // Create an local session description based on this.
+  const cricket::SessionDescription* local_desc =
+      provider_->ProvideAnswer(options);
 
-  // Use the MediaSessionFactory to create an SDP answer.
-  talk_base::scoped_ptr<cricket::SessionDescription> answer(
-      session_description_factory_.CreateAnswer(message->desc(), options));
-
-  scoped_refptr<PeerConnectionMessage> answer_message;
-  if (VerifyAnswer(answer.get())) {
-    answer_message = PeerConnectionMessage::Create(
-        PeerConnectionMessage::kAnswer, answer.release(), candidates_);
+  talk_base::scoped_ptr<PeerConnectionMessage> answer_message;
+  if (!VerifyAnswer(local_desc)) {
+    answer_message.reset(PeerConnectionMessage::CreateErrorMessage(
+        PeerConnectionMessage::kOfferNotAcceptable));
 
-  } else {
-    answer_message = PeerConnectionMessage::CreateErrorMessage(
-        PeerConnectionMessage::kOfferNotAcceptable);
+    // Signal that the new answer is ready to be sent.
+    SignalNewPeerConnectionMessage(answer_message->Serialize());
+    return;
   }
-  // Signal the resulting local and remote session description.
-  SignalUpdateSessionDescription(answer.get(),
-                                 message->desc(),
-                                 message->candidates()); // remote candidates
 
-  UpdateRemoteStreams(message->desc());
+  answer_message.reset(PeerConnectionMessage::Create(
+      PeerConnectionMessage::kAnswer, local_desc, candidates_));
+
+  // Let the provider know the negotiation is done.
+  provider_->NegotiationDone();
 
-  // Signal that the new answer is ready to be sent.
   SignalNewPeerConnectionMessage(answer_message->Serialize());
 
-  // Start send the local streams.
-  // TODO(perkj): Defer the start of sending local media so the remote peer
-  // have time to receive the signaling message before media arrives?
-  // This is under debate.
+  UpdateRemoteStreams(message->desc());
+
+  // Update the state of the local streams.
   UpdateSendingLocalStreams(answer_message->desc(), local_streams);
 }
 
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling.h b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling.h
index d9532c918b..bc5e6b3446 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling.h
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling.h
@@ -42,6 +42,8 @@
 #include "talk/app/webrtc_dev/peerconnectionmessage.h"
 #include "talk/app/webrtc_dev/ref_count.h"
 #include "talk/app/webrtc_dev/scoped_refptr.h"
+#include "talk/app/webrtc_dev/sessiondescriptionprovider.h"
+#include "talk/app/webrtc_dev/webrtcsessionobserver.h"
 #include "talk/base/basictypes.h"
 #include "talk/base/messagehandler.h"
 #include "talk/base/scoped_ptr.h"
@@ -70,7 +72,8 @@ namespace webrtc {
 // Before PeerConnectionSignaling can process an answer or create an offer,
 // Initialize have to be called. The last request to create an offer or process
 // an answer will be processed after Initialize have been called.
-class PeerConnectionSignaling : public talk_base::MessageHandler {
+class PeerConnectionSignaling : public WebRtcSessionObserver,
+                                public talk_base::MessageHandler {
  public:
   enum State {
     // Awaiting the local candidates.
@@ -85,12 +88,10 @@ class PeerConnectionSignaling : public talk_base::MessageHandler {
     kGlare
   };
 
-  PeerConnectionSignaling(cricket::ChannelManager* channel_manager,
-                          talk_base::Thread* signaling_thread);
+  PeerConnectionSignaling(talk_base::Thread* signaling_thread,
+                          SessionDescriptionProvider* provider);
   ~PeerConnectionSignaling();
 
-  void Initialize(const cricket::Candidates& candidates);
-
   // Process a received offer/answer from the remote peer.
   void ProcessSignalingMessage(const std::string& message,
                                StreamCollection* local_streams);
@@ -118,17 +119,13 @@ class PeerConnectionSignaling : public talk_base::MessageHandler {
   // Remote PeerConnection sent an error message.
   sigslot::signal1<PeerConnectionMessage::ErrorCode> SignalErrorMessageReceived;
 
-  // Informs that a new Offer/Answer have been exchanged.
-  // The parameters are local session description,
-  //                    remote session_description,
-  //                    local StreamCollection.
-  sigslot::signal3<const cricket::SessionDescription*,
-                   const cricket::SessionDescription*,
-                   const cricket::Candidates&> SignalUpdateSessionDescription;
+  // Implements WebRtcSessionObserver
+  virtual void OnCandidatesReady(const cricket::Candidates& candidates);
+  // Implements talk_base::MessageHandler.
+  virtual void OnMessage(talk_base::Message* msg);
 
  private:
-  // Implement talk_base::MessageHandler.
-  virtual void OnMessage(talk_base::Message* msg);
+
   void CreateOffer_s();
   void CreateAnswer_s();
 
@@ -143,11 +140,12 @@ class PeerConnectionSignaling : public talk_base::MessageHandler {
   typedef std::list<scoped_refptr<StreamCollection> > StreamCollectionList;
   StreamCollectionList queued_offers_;
 
-  typedef std::pair<scoped_refptr<PeerConnectionMessage>,
+  typedef std::pair<PeerConnectionMessage*,
                     scoped_refptr<StreamCollection> >  RemoteOfferPair;
   RemoteOfferPair queued_received_offer_;
 
   talk_base::Thread* signaling_thread_;
+  SessionDescriptionProvider* provider_;
   State state_;
   uint32 ssrc_counter_;
 
@@ -157,9 +155,6 @@ class PeerConnectionSignaling : public talk_base::MessageHandler {
   typedef std::map<std::string, scoped_refptr<MediaStream> >
       LocalStreamMap;
   LocalStreamMap local_streams_;
-  cricket::MediaSessionDescriptionFactory session_description_factory_;
-
-  scoped_refptr<PeerConnectionMessage> last_send_offer_;
   cricket::Candidates candidates_;
 };
 
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling_unittest.cc b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling_unittest.cc
index 15e6c16b57..86c17bea14 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling_unittest.cc
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/peerconnectionsignaling_unittest.cc
@@ -82,8 +82,7 @@ class MockMediaStreamObserver : public webrtc::Observer {
 class MockSignalingObserver : public sigslot::has_slots<> {
  public:
   MockSignalingObserver()
-      : update_session_description_counter_(0),
-        remote_peer_(NULL) {
+      : remote_peer_(NULL) {
   }
 
   // New remote stream have been discovered.
@@ -108,20 +107,14 @@ class MockSignalingObserver : public sigslot::has_slots<> {
       // the message.
       talk_base::Thread::Current()->ProcessMessages(1);
     }
-    scoped_refptr<PeerConnectionMessage> message;
-    message = PeerConnectionMessage::Create(smessage);
+    talk_base::scoped_ptr<PeerConnectionMessage> message(
+        PeerConnectionMessage::Create(smessage));
     if (message.get() != NULL &&
         message->type() != PeerConnectionMessage::kError) {
       last_message = smessage;
     }
   }
 
-  void OnUpdateSessionDescription(const cricket::SessionDescription* local,
-                                  const cricket::SessionDescription* remote,
-                                  const cricket::Candidates& candidates) {
-    update_session_description_counter_++;
-  }
-
   // Tell this object to answer the remote_peer.
   // remote_local_collection is the local collection the remote peer want to
   // send in an answer.
@@ -146,40 +139,80 @@ class MockSignalingObserver : public sigslot::has_slots<> {
   virtual ~MockSignalingObserver() {}
 
   std::string last_message;
-  int update_session_description_counter_;
-
  private:
   MediaStreamMap remote_media_streams_;
   scoped_refptr<StreamCollectionImpl> remote_local_collection_;
   PeerConnectionSignaling* remote_peer_;
 };
 
+class MockSessionDescriptionProvider : public SessionDescriptionProvider {
+ public:
+  MockSessionDescriptionProvider(cricket::ChannelManager* channel_manager)
+      : update_session_description_counter_(0),
+        session_description_factory_(
+          new cricket::MediaSessionDescriptionFactory(channel_manager)) {
+  }
+  virtual const cricket::SessionDescription* ProvideOffer(
+      const cricket::MediaSessionOptions& options) {
+    offer_.reset(session_description_factory_->CreateOffer(options));
+    return offer_.get();
+  }
+
+  // Transfer ownership of remote_offer.
+  virtual const cricket::SessionDescription* SetRemoteSessionDescription(
+      const cricket::SessionDescription* remote_offer,
+      const cricket::Candidates& remote_candidates) {
+    remote_desc_.reset(remote_offer);
+    return remote_desc_.get();
+  }
+
+  virtual const cricket::SessionDescription* ProvideAnswer(
+      const cricket::MediaSessionOptions& options) {
+    answer_.reset(session_description_factory_->CreateAnswer(remote_desc_.get(),
+                                                             options));
+    return answer_.get();
+  }
+
+  virtual void NegotiationDone() {
+    ++update_session_description_counter_;
+  }
+
+  int update_session_description_counter_;
+
+ protected:
+  talk_base::scoped_ptr<cricket::MediaSessionDescriptionFactory>
+      session_description_factory_;
+  talk_base::scoped_ptr<const cricket::SessionDescription> offer_;
+  talk_base::scoped_ptr<const cricket::SessionDescription> answer_;
+  talk_base::scoped_ptr<const cricket::SessionDescription> remote_desc_;
+};
+
 class PeerConnectionSignalingTest: public testing::Test {
  protected:
   virtual void SetUp() {
     channel_manager_.reset(new cricket::ChannelManager(
         talk_base::Thread::Current()));
     EXPECT_TRUE(channel_manager_->Init());
+    provider1_.reset(new MockSessionDescriptionProvider(
+        channel_manager_.get()));
+    provider2_.reset(new MockSessionDescriptionProvider(
+        channel_manager_.get()));
 
     signaling1_.reset(new PeerConnectionSignaling(
-        channel_manager_.get(), talk_base::Thread::Current()));
+        talk_base::Thread::Current(), provider1_.get()));
     observer1_.reset(new MockSignalingObserver());
     signaling1_->SignalNewPeerConnectionMessage.connect(
         observer1_.get(), &MockSignalingObserver::OnSignalingMessage);
-    signaling1_->SignalUpdateSessionDescription.connect(
-        observer1_.get(), &MockSignalingObserver::OnUpdateSessionDescription);
     signaling1_->SignalRemoteStreamAdded.connect(
         observer1_.get(), &MockSignalingObserver::OnRemoteStreamAdded);
     signaling1_->SignalRemoteStreamRemoved.connect(
         observer1_.get(), &MockSignalingObserver::OnRemoteStreamRemoved);
 
     signaling2_.reset(new PeerConnectionSignaling(
-        channel_manager_.get(), talk_base::Thread::Current()));
+        talk_base::Thread::Current(), provider2_.get()));
     observer2_.reset(new MockSignalingObserver());
     signaling2_->SignalNewPeerConnectionMessage.connect(
         observer2_.get(), &MockSignalingObserver::OnSignalingMessage);
-    signaling2_->SignalUpdateSessionDescription.connect(
-        observer2_.get(), &MockSignalingObserver::OnUpdateSessionDescription);
     signaling2_->SignalRemoteStreamAdded.connect(
         observer2_.get(), &MockSignalingObserver::OnRemoteStreamAdded);
     signaling2_->SignalRemoteStreamRemoved.connect(
@@ -189,6 +222,8 @@ class PeerConnectionSignalingTest: public testing::Test {
   cricket::Candidates candidates_;
   talk_base::scoped_ptr<MockSignalingObserver> observer1_;
   talk_base::scoped_ptr<MockSignalingObserver> observer2_;
+  talk_base::scoped_ptr<MockSessionDescriptionProvider> provider1_;
+  talk_base::scoped_ptr<MockSessionDescriptionProvider> provider2_;
   talk_base::scoped_ptr<PeerConnectionSignaling> signaling1_;
   talk_base::scoped_ptr<PeerConnectionSignaling> signaling2_;
   talk_base::scoped_ptr<cricket::ChannelManager> channel_manager_;
@@ -233,7 +268,7 @@ TEST_F(PeerConnectionSignalingTest, SimpleOneWayCall) {
   EXPECT_EQ(PeerConnectionSignaling::kInitializing, signaling1_->GetState());
 
   // Initialize signaling1_ by providing the candidates.
-  signaling1_->Initialize(candidates_);
+  signaling1_->OnCandidatesReady(candidates_);
   EXPECT_EQ(PeerConnectionSignaling::kWaitingForAnswer,
             signaling1_->GetState());
   // Process posted messages to allow signaling_1 to send the offer.
@@ -244,7 +279,7 @@ TEST_F(PeerConnectionSignalingTest, SimpleOneWayCall) {
   EXPECT_EQ(PeerConnectionSignaling::kInitializing, signaling2_->GetState());
 
   // Provide the candidates to signaling_2 and let it process the offer.
-  signaling2_->Initialize(candidates_);
+  signaling2_->OnCandidatesReady(candidates_);
   talk_base::Thread::Current()->ProcessMessages(1);
 
   // Verify that the offer/answer have been exchanged and the state is good.
@@ -260,14 +295,14 @@ TEST_F(PeerConnectionSignalingTest, SimpleOneWayCall) {
   EXPECT_TRUE(observer2_->RemoteStream(label) != NULL);
 
   // Verify that both peers have updated the session descriptions.
-  EXPECT_EQ(1u, observer1_->update_session_description_counter_);
-  EXPECT_EQ(1u, observer2_->update_session_description_counter_);
+  EXPECT_EQ(1u, provider1_->update_session_description_counter_);
+  EXPECT_EQ(1u, provider2_->update_session_description_counter_);
 }
 
 TEST_F(PeerConnectionSignalingTest, Glare) {
   // Initialize signaling1_ and signaling_2 by providing the candidates.
-  signaling1_->Initialize(candidates_);
-  signaling2_->Initialize(candidates_);
+  signaling1_->OnCandidatesReady(candidates_);
+  signaling2_->OnCandidatesReady(candidates_);
   // Create a local stream.
   std::string label(kStreamLabel1);
   scoped_refptr<LocalMediaStream> stream(CreateLocalMediaStream(label));
@@ -323,14 +358,14 @@ TEST_F(PeerConnectionSignalingTest, Glare) {
   EXPECT_TRUE(observer2_->RemoteStream(label) != NULL);
 
   // Verify that both peers have updated the session descriptions.
-  EXPECT_EQ(1u, observer1_->update_session_description_counter_);
-  EXPECT_EQ(1u, observer2_->update_session_description_counter_);
+  EXPECT_EQ(1u, provider1_->update_session_description_counter_);
+  EXPECT_EQ(1u, provider2_->update_session_description_counter_);
 }
 
 TEST_F(PeerConnectionSignalingTest, AddRemoveStream) {
   // Initialize signaling1_ and signaling_2 by providing the candidates.
-  signaling1_->Initialize(candidates_);
-  signaling2_->Initialize(candidates_);
+  signaling1_->OnCandidatesReady(candidates_);
+  signaling2_->OnCandidatesReady(candidates_);
   // Create a local stream.
   std::string label(kStreamLabel1);
   scoped_refptr<LocalMediaStream> stream(CreateLocalMediaStream(label));
@@ -367,8 +402,8 @@ TEST_F(PeerConnectionSignalingTest, AddRemoveStream) {
   talk_base::Thread::Current()->ProcessMessages(1);
 
   // Verify that both peers have updated the session descriptions.
-  EXPECT_EQ(1u, observer1_->update_session_description_counter_);
-  EXPECT_EQ(1u, observer2_->update_session_description_counter_);
+  EXPECT_EQ(1u, provider1_->update_session_description_counter_);
+  EXPECT_EQ(1u, provider2_->update_session_description_counter_);
 
   // Peer2 add a stream.
   local_collection2->AddStream(stream);
@@ -384,8 +419,8 @@ TEST_F(PeerConnectionSignalingTest, AddRemoveStream) {
   EXPECT_TRUE(observer1_->RemoteStream(label) != NULL);
 
   // Verify that both peers have updated the session descriptions.
-  EXPECT_EQ(2u, observer1_->update_session_description_counter_);
-  EXPECT_EQ(2u, observer2_->update_session_description_counter_);
+  EXPECT_EQ(2u, provider1_->update_session_description_counter_);
+  EXPECT_EQ(2u, provider2_->update_session_description_counter_);
 
   // Remove the stream
   local_collection2->RemoveStream(stream);
@@ -401,8 +436,8 @@ TEST_F(PeerConnectionSignalingTest, AddRemoveStream) {
   EXPECT_EQ(MediaStreamTrack::kEnded, track_observer1.track_state);
 
   // Verify that both peers have updated the session descriptions.
-  EXPECT_EQ(3u, observer1_->update_session_description_counter_);
-  EXPECT_EQ(3u, observer2_->update_session_description_counter_);
+  EXPECT_EQ(3u, provider1_->update_session_description_counter_);
+  EXPECT_EQ(3u, provider2_->update_session_description_counter_);
 }
 
 }  // namespace webrtc
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/sessiondescriptionprovider.h b/third_party_mods/libjingle/source/talk/app/webrtc_dev/sessiondescriptionprovider.h
new file mode 100644
index 0000000000..f0a7645423
--- /dev/null
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/sessiondescriptionprovider.h
@@ -0,0 +1,58 @@
+/*
+ * libjingle
+ * Copyright 2011, Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef TALK_APP_WEBRTC_SESSIONDESCRIPTIONPROVIDER_H_
+#define TALK_APP_WEBRTC_SESSIONDESCRIPTIONPROVIDER_H_
+
+#include "talk/session/phone/mediasession.h"
+#include "talk/p2p/base/candidate.h"
+#include "talk/p2p/base/sessiondescription.h"
+
+namespace webrtc {
+
+class SessionDescriptionProvider {
+ public:
+  virtual const cricket::SessionDescription* ProvideOffer(
+      const cricket::MediaSessionOptions& options) = 0;
+
+  // Transfer ownership of remote_offer.
+  virtual const cricket::SessionDescription* SetRemoteSessionDescription(
+      const cricket::SessionDescription* remote_offer,
+      const std::vector<cricket::Candidate>& remote_candidates) = 0;
+
+  virtual const cricket::SessionDescription* ProvideAnswer(
+      const cricket::MediaSessionOptions& options) = 0;
+
+  virtual void NegotiationDone() = 0;
+
+ protected:
+  virtual ~SessionDescriptionProvider() {}
+};
+
+}  // namespace webrtc
+
+#endif  // TALK_APP_WEBRTC_SESSIONDESCRIPTIONPROVIDER_H_
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession.cc b/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession.cc
index 9dcc7b2b38..06ce50a8e8 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession.cc
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession.cc
@@ -58,15 +58,14 @@ static const std::string kRtcpVideoChannelStr = "video_rtcp";
 WebRtcSession::WebRtcSession(cricket::ChannelManager* channel_manager,
                              talk_base::Thread* signaling_thread,
                              talk_base::Thread* worker_thread,
-                             cricket::PortAllocator* port_allocator,
-                             PeerConnectionSignaling* pc_signaling)
-    : cricket::BaseSession(signaling_thread, worker_thread, port_allocator,
+                             cricket::PortAllocator* port_allocator)
+    : observer_(NULL),
+      cricket::BaseSession(signaling_thread, worker_thread, port_allocator,
                            talk_base::ToString(talk_base::CreateRandomId()),
                            cricket::NS_JINGLE_RTP, true) {
   // TODO(mallinath) - Remove initiator flag from BaseSession. As it's being
   // used only by cricket::Session.
   channel_manager_ = channel_manager;
-  pc_signaling_ = pc_signaling;
 }
 
 WebRtcSession::~WebRtcSession() {
@@ -74,9 +73,6 @@ WebRtcSession::~WebRtcSession() {
 }
 
 bool WebRtcSession::Initialize() {
-  ASSERT(pc_signaling_ != NULL);
-  pc_signaling_->SignalUpdateSessionDescription.connect(
-      this, &WebRtcSession::OnSignalUpdateSessionDescription);
   return CreateChannels();
 }
 
@@ -217,7 +213,8 @@ void WebRtcSession::OnTransportCandidatesReady(
     return;
   InsertTransportCandidates(candidates);
   if (local_candidates_.size() == kAllowedCandidates) {
-    pc_signaling_->Initialize(local_candidates_);
+    if(observer_)
+      observer_->OnCandidatesReady(local_candidates_);
     // TODO(mallinath) - Remove signal when a new interface added for
     // PC signaling.
     SignalCandidatesReady(this, local_candidates_);
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession.h b/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession.h
index 9968e6c373..ab4b3e432c 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession.h
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession.h
@@ -36,6 +36,8 @@
 #include "talk/p2p/base/session.h"
 #include "talk/session/phone/mediasession.h"
 #include "talk/app/webrtc_dev/mediastreamprovider.h"
+#include "talk/app/webrtc_dev/sessiondescriptionprovider.h"
+#include "talk/app/webrtc_dev/webrtcsessionobserver.h"
 
 namespace cricket {
 class ChannelManager;
@@ -51,13 +53,13 @@ class PeerConnectionSignaling;
 class StreamCollection;
 
 class WebRtcSession : public cricket::BaseSession,
-                      public MediaProviderInterface {
+                      public MediaProviderInterface,
+                      public SessionDescriptionProvider {
  public:
   WebRtcSession(cricket::ChannelManager* channel_manager,
                 talk_base::Thread* signaling_thread,
                 talk_base::Thread* worker_thread,
-                cricket::PortAllocator* port_allocator,
-                PeerConnectionSignaling* pc_signaling);
+                cricket::PortAllocator* port_allocator);
   ~WebRtcSession();
 
   bool Initialize();
@@ -88,12 +90,23 @@ class WebRtcSession : public cricket::BaseSession,
   virtual void SetRemoteRenderer(uint32 ssrc,
                                  cricket::VideoRenderer* renderer);
 
-  // Callback handling from PeerConnectionSignaling
+  //TODO mallinath: remove.
   void OnSignalUpdateSessionDescription(
       const cricket::SessionDescription* local_desc,
       const cricket::SessionDescription* remote_desc,
       const cricket::Candidates& remote_candidates);
 
+  // Implements SessionDescriptionProvider
+  virtual const cricket::SessionDescription* ProvideOffer(
+      const cricket::MediaSessionOptions& options) {}
+  virtual const cricket::SessionDescription* SetRemoteSessionDescription(
+      const cricket::SessionDescription* remote_offer,
+      const cricket::Candidates& remote_candidates) {}
+  virtual const cricket::SessionDescription* ProvideAnswer(
+      const cricket::MediaSessionOptions& options) {}
+  virtual void NegotiationDone() {}
+
+
   // Transport related callbacks, override from cricket::BaseSession.
   virtual void OnTransportRequestSignaling(cricket::Transport* transport);
   virtual void OnTransportConnecting(cricket::Transport* transport);
@@ -122,7 +135,7 @@ class WebRtcSession : public cricket::BaseSession,
   void ProcessRemoteMediaChanges(const cricket::SessionDescription* sdesc);
 
  private:
-  PeerConnectionSignaling* pc_signaling_;
+  WebRtcSessionObserver* observer_;
   talk_base::scoped_ptr<cricket::VoiceChannel> voice_channel_;
   talk_base::scoped_ptr<cricket::VideoChannel> video_channel_;
   cricket::ChannelManager* channel_manager_;
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession_unittest.cc b/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession_unittest.cc
index d2c7ea2785..d32feaca38 100644
--- a/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession_unittest.cc
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsession_unittest.cc
@@ -48,9 +48,6 @@ class WebRtcSessionTest : public testing::Test,
     channel_manager_.reset(new cricket::ChannelManager(worker_thread_));
     port_allocator_.reset(
         new cricket::FakePortAllocator(worker_thread_, NULL));
-    pc_signaling_.reset(
-        new webrtc::PeerConnectionSignaling(channel_manager_.get(),
-                                            signaling_thread_));
     media_factory_ =
         new cricket::MediaSessionDescriptionFactory(channel_manager_.get());
   }
@@ -77,7 +74,7 @@ class WebRtcSessionTest : public testing::Test,
     EXPECT_TRUE(channel_manager_.get()->Init());
     session_.reset(new webrtc::WebRtcSession(
         channel_manager_.get(), worker_thread_, signaling_thread_,
-        port_allocator_.get(), pc_signaling_.get()));
+        port_allocator_.get()));
     session_->SignalCandidatesReady.connect(
         this, &WebRtcSessionTest::OnCandidatesReady);
     EXPECT_TRUE(InitializeSession());
@@ -113,7 +110,6 @@ class WebRtcSessionTest : public testing::Test,
   talk_base::Thread* signaling_thread_;
   talk_base::Thread* worker_thread_;
   talk_base::scoped_ptr<cricket::PortAllocator> port_allocator_;
-  talk_base::scoped_ptr<webrtc::PeerConnectionSignaling> pc_signaling_;
   talk_base::scoped_ptr<webrtc::WebRtcSession> session_;
   talk_base::scoped_ptr<cricket::ChannelManager> channel_manager_;
 };
diff --git a/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsessionobserver.h b/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsessionobserver.h
new file mode 100644
index 0000000000..c1653c93e7
--- /dev/null
+++ b/third_party_mods/libjingle/source/talk/app/webrtc_dev/webrtcsessionobserver.h
@@ -0,0 +1,47 @@
+/*
+ * libjingle
+ * Copyright 2011, Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef TALK_APP_WEBRTC_WEBRTCSESSIONOBSERVER_H_
+#define TALK_APP_WEBRTC_WEBRTCSESSIONOBSERVER_H_
+
+#include <vector>
+
+#include "talk/p2p/base/candidate.h"
+
+namespace webrtc {
+
+class WebRtcSessionObserver {
+ public:
+  virtual void OnCandidatesReady(
+      const std::vector<cricket::Candidate>& candiddates) = 0;
+ protected:
+  virtual ~WebRtcSessionObserver() {}
+};
+
+}  // namespace webrtc
+
+#endif  // TALK_APP_WEBRTC_WEBRTCSESSIONOBSERVER_H_