remoting/host/cast_extension_session.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "remoting/host/cast_extension_session.h"
   6
   7 #include "base/bind.h"
   8 #include "base/json/json_reader.h"
   9 #include "base/json/json_writer.h"
  10 #include "base/logging.h"
  11 #include "base/synchronization/waitable_event.h"
  12 #include "net/url_request/url_request_context_getter.h"
  13 #include "remoting/host/cast_video_capturer_adapter.h"
  14 #include "remoting/host/chromium_port_allocator_factory.h"
  15 #include "remoting/host/client_session.h"
  16 #include "remoting/proto/control.pb.h"
  17 #include "remoting/protocol/client_stub.h"
  18 #include "third_party/libjingle/source/talk/app/webrtc/mediastreaminterface.h"
  19 #include "third_party/libjingle/source/talk/app/webrtc/test/fakeconstraints.h"
  20 #include "third_party/libjingle/source/talk/app/webrtc/videosourceinterface.h"
  21
  22 namespace remoting {
  23
  24 // Used as the type attribute of all Cast protocol::ExtensionMessages.
  25 const char kExtensionMessageType[] = "cast_message";
  26
  27 // Top-level keys used in all extension messages between host and client.
  28 // Must keep synced with webapp.
  29 const char kTopLevelData[] = "chromoting_data";
  30 const char kTopLevelSubject[] = "subject";
  31
  32 // Keys used to describe the subject of a cast extension message. WebRTC-related
  33 // message subjects are prepended with "webrtc_".
  34 // Must keep synced with webapp.
  35 const char kSubjectReady[] = "ready";
  36 const char kSubjectTest[] = "test";
  37 const char kSubjectNewCandidate[] = "webrtc_candidate";
  38 const char kSubjectOffer[] = "webrtc_offer";
  39 const char kSubjectAnswer[] = "webrtc_answer";
  40
  41 // WebRTC headers used inside messages with subject = "webrtc_*".
  42 const char kWebRtcCandidate[] = "candidate";
  43 const char kWebRtcSessionDescType[] = "type";
  44 const char kWebRtcSessionDescSDP[] = "sdp";
  45 const char kWebRtcSDPMid[] = "sdpMid";
  46 const char kWebRtcSDPMLineIndex[] = "sdpMLineIndex";
  47
  48 // Media labels used over the PeerConnection.
  49 const char kVideoLabel[] = "cast_video_label";
  50 const char kStreamLabel[] = "stream_label";
  51
  52 // Default STUN server used to construct
  53 // webrtc::PeerConnectionInterface::RTCConfiguration for the PeerConnection.
  54 const char kDefaultStunURI[] = "stun:stun.l.google.com:19302";
  55
  56 const char kWorkerThreadName[] = "CastExtensionSessionWorkerThread";
  57
  58 // Interval between each call to PollPeerConnectionStats().
  59 const int kStatsLogIntervalSec = 10;
  60
  61 // Minimum frame rate for video streaming over the PeerConnection in frames per
  62 // second, added as a media constraint when constructing the video source for
  63 // the Peer Connection.
  64 const int kMinFramesPerSecond = 5;
  65
  66 // A webrtc::SetSessionDescriptionObserver implementation used to receive the
  67 // results of setting local and remote descriptions of the PeerConnection.
  68 class CastSetSessionDescriptionObserver
  69     : public webrtc::SetSessionDescriptionObserver {
  70  public:
  71   static CastSetSessionDescriptionObserver* Create() {
  72     return new rtc::RefCountedObject<CastSetSessionDescriptionObserver>();
  73   }
  74   virtual void OnSuccess() override {
  75     VLOG(1) << "Setting session description succeeded.";
  76   }
  77   virtual void OnFailure(const std::string& error) override {
  78     LOG(ERROR) << "Setting session description failed: " << error;
  79   }
  80
  81  protected:
  82   CastSetSessionDescriptionObserver() {}
  83   virtual ~CastSetSessionDescriptionObserver() {}
  84
  85   DISALLOW_COPY_AND_ASSIGN(CastSetSessionDescriptionObserver);
  86 };
  87
  88 // A webrtc::CreateSessionDescriptionObserver implementation used to receive the
  89 // results of creating descriptions for this end of the PeerConnection.
  90 class CastCreateSessionDescriptionObserver
  91     : public webrtc::CreateSessionDescriptionObserver {
  92  public:
  93   static CastCreateSessionDescriptionObserver* Create(
  94       CastExtensionSession* session) {
  95     return new rtc::RefCountedObject<CastCreateSessionDescriptionObserver>(
  96         session);
  97   }
  98   virtual void OnSuccess(webrtc::SessionDescriptionInterface* desc) override {
  99     if (cast_extension_session_ == NULL) {
 100       LOG(ERROR)
 101           << "No CastExtensionSession. Creating session description succeeded.";
 102       return;
 103     }
 104     cast_extension_session_->OnCreateSessionDescription(desc);
 105   }
 106   virtual void OnFailure(const std::string& error) override {
 107     if (cast_extension_session_ == NULL) {
 108       LOG(ERROR)
 109           << "No CastExtensionSession. Creating session description failed.";
 110       return;
 111     }
 112     cast_extension_session_->OnCreateSessionDescriptionFailure(error);
 113   }
 114   void SetCastExtensionSession(CastExtensionSession* cast_extension_session) {
 115     cast_extension_session_ = cast_extension_session;
 116   }
 117
 118  protected:
 119   explicit CastCreateSessionDescriptionObserver(CastExtensionSession* session)
 120       : cast_extension_session_(session) {}
 121   virtual ~CastCreateSessionDescriptionObserver() {}
 122
 123  private:
 124   CastExtensionSession* cast_extension_session_;
 125
 126   DISALLOW_COPY_AND_ASSIGN(CastCreateSessionDescriptionObserver);
 127 };
 128
 129 // A webrtc::StatsObserver implementation used to receive statistics about the
 130 // current PeerConnection.
 131 class CastStatsObserver : public webrtc::StatsObserver {
 132  public:
 133   static CastStatsObserver* Create() {
 134     return new rtc::RefCountedObject<CastStatsObserver>();
 135   }
 136
 137   virtual void OnComplete(
 138       const std::vector<webrtc::StatsReport>& reports) override {
 139     typedef webrtc::StatsReport::Values::iterator ValuesIterator;
 140
 141     VLOG(1) << "Received " << reports.size() << " new StatsReports.";
 142
 143     int index;
 144     std::vector<webrtc::StatsReport>::const_iterator it;
 145     for (it = reports.begin(), index = 0; it != reports.end(); ++it, ++index) {
 146       webrtc::StatsReport::Values v = it->values;
 147       VLOG(1) << "Report " << index << ":";
 148       for (ValuesIterator vIt = v.begin(); vIt != v.end(); ++vIt) {
 149         VLOG(1) << "Stat: " << vIt->name << "=" << vIt->value << ".";
 150       }
 151     }
 152   }
 153
 154  protected:
 155   CastStatsObserver() {}
 156   virtual ~CastStatsObserver() {}
 157
 158   DISALLOW_COPY_AND_ASSIGN(CastStatsObserver);
 159 };
 160
 161 // TODO(aiguha): Fix PeerConnnection-related tear down crash caused by premature
 162 // destruction of cricket::CaptureManager (which occurs on releasing
 163 // |peer_conn_factory_|). See crbug.com/403840.
 164 CastExtensionSession::~CastExtensionSession() {
 165   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 166
 167   // Explicitly clear |create_session_desc_observer_|'s pointer to |this|,
 168   // since the CastExtensionSession is destructing. Otherwise,
 169   // |create_session_desc_observer_| would be left with a dangling pointer.
 170   create_session_desc_observer_->SetCastExtensionSession(NULL);
 171
 172   CleanupPeerConnection();
 173 }
 174
 175 // static
 176 scoped_ptr<CastExtensionSession> CastExtensionSession::Create(
 177     scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
 178     scoped_refptr<net::URLRequestContextGetter> url_request_context_getter,
 179     const protocol::NetworkSettings& network_settings,
 180     ClientSessionControl* client_session_control,
 181     protocol::ClientStub* client_stub) {
 182   scoped_ptr<CastExtensionSession> cast_extension_session(
 183       new CastExtensionSession(caller_task_runner,
 184                                url_request_context_getter,
 185                                network_settings,
 186                                client_session_control,
 187                                client_stub));
 188   if (!cast_extension_session->WrapTasksAndSave() ||
 189       !cast_extension_session->InitializePeerConnection()) {
 190     return nullptr;
 191   }
 192   return cast_extension_session.Pass();
 193 }
 194
 195 void CastExtensionSession::OnCreateSessionDescription(
 196     webrtc::SessionDescriptionInterface* desc) {
 197   if (!caller_task_runner_->BelongsToCurrentThread()) {
 198     caller_task_runner_->PostTask(
 199         FROM_HERE,
 200         base::Bind(&CastExtensionSession::OnCreateSessionDescription,
 201                    base::Unretained(this),
 202                    desc));
 203     return;
 204   }
 205
 206   peer_connection_->SetLocalDescription(
 207       CastSetSessionDescriptionObserver::Create(), desc);
 208
 209   scoped_ptr<base::DictionaryValue> json(new base::DictionaryValue());
 210   json->SetString(kWebRtcSessionDescType, desc->type());
 211   std::string subject =
 212       (desc->type() == "offer") ? kSubjectOffer : kSubjectAnswer;
 213   std::string desc_str;
 214   desc->ToString(&desc_str);
 215   json->SetString(kWebRtcSessionDescSDP, desc_str);
 216   std::string json_str;
 217   if (!base::JSONWriter::Write(json.get(), &json_str)) {
 218     LOG(ERROR) << "Failed to serialize sdp message.";
 219     return;
 220   }
 221
 222   SendMessageToClient(subject.c_str(), json_str);
 223 }
 224
 225 void CastExtensionSession::OnCreateSessionDescriptionFailure(
 226     const std::string& error) {
 227   VLOG(1) << "Creating Session Description failed: " << error;
 228 }
 229
 230 // TODO(aiguha): Support the case(s) where we've grabbed the capturer already,
 231 // but another extension reset the video pipeline. We should remove the
 232 // stream from the peer connection here, and then attempt to re-setup the
 233 // peer connection in the OnRenegotiationNeeded() callback.
 234 // See crbug.com/403843.
 235 void CastExtensionSession::OnCreateVideoCapturer(
 236     scoped_ptr<webrtc::DesktopCapturer>* capturer) {
 237   if (has_grabbed_capturer_) {
 238     LOG(ERROR) << "The video pipeline was reset unexpectedly.";
 239     has_grabbed_capturer_ = false;
 240     peer_connection_->RemoveStream(stream_.release());
 241     return;
 242   }
 243
 244   if (received_offer_) {
 245     has_grabbed_capturer_ = true;
 246     if (SetupVideoStream(capturer->Pass())) {
 247       peer_connection_->CreateAnswer(create_session_desc_observer_, NULL);
 248     } else {
 249       has_grabbed_capturer_ = false;
 250       // Ignore the received offer, since we failed to setup a video stream.
 251       received_offer_ = false;
 252     }
 253     return;
 254   }
 255 }
 256
 257 bool CastExtensionSession::ModifiesVideoPipeline() const {
 258   return true;
 259 }
 260
 261 // Returns true if the |message| is a Cast ExtensionMessage, even if
 262 // it was badly formed or a resulting action failed. This is done so that
 263 // the host does not continue to attempt to pass |message| to other
 264 // HostExtensionSessions.
 265 bool CastExtensionSession::OnExtensionMessage(
 266     ClientSessionControl* client_session_control,
 267     protocol::ClientStub* client_stub,
 268     const protocol::ExtensionMessage& message) {
 269   if (message.type() != kExtensionMessageType) {
 270     return false;
 271   }
 272
 273   scoped_ptr<base::Value> value(base::JSONReader::Read(message.data()));
 274   base::DictionaryValue* client_message;
 275   if (!(value && value->GetAsDictionary(&client_message))) {
 276     LOG(ERROR) << "Could not read cast extension message.";
 277     return true;
 278   }
 279
 280   std::string subject;
 281   if (!client_message->GetString(kTopLevelSubject, &subject)) {
 282     LOG(ERROR) << "Invalid Cast Extension Message (missing subject header).";
 283     return true;
 284   }
 285
 286   if (subject == kSubjectOffer && !received_offer_) {
 287     // Reset the video pipeline so we can grab the screen capturer and setup
 288     // a video stream.
 289     if (ParseAndSetRemoteDescription(client_message)) {
 290       received_offer_ = true;
 291       LOG(INFO) << "About to ResetVideoPipeline.";
 292       client_session_control_->ResetVideoPipeline();
 293
 294     }
 295   } else if (subject == kSubjectAnswer) {
 296     ParseAndSetRemoteDescription(client_message);
 297   } else if (subject == kSubjectNewCandidate) {
 298     ParseAndAddICECandidate(client_message);
 299   } else {
 300     VLOG(1) << "Unexpected CastExtension Message: " << message.data();
 301   }
 302   return true;
 303 }
 304
 305 // Private methods ------------------------------------------------------------
 306
 307 CastExtensionSession::CastExtensionSession(
 308     scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
 309     scoped_refptr<net::URLRequestContextGetter> url_request_context_getter,
 310     const protocol::NetworkSettings& network_settings,
 311     ClientSessionControl* client_session_control,
 312     protocol::ClientStub* client_stub)
 313     : caller_task_runner_(caller_task_runner),
 314       url_request_context_getter_(url_request_context_getter),
 315       network_settings_(network_settings),
 316       client_session_control_(client_session_control),
 317       client_stub_(client_stub),
 318       stats_observer_(CastStatsObserver::Create()),
 319       received_offer_(false),
 320       has_grabbed_capturer_(false),
 321       signaling_thread_wrapper_(NULL),
 322       worker_thread_wrapper_(NULL),
 323       worker_thread_(kWorkerThreadName) {
 324   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 325   DCHECK(url_request_context_getter_.get());
 326   DCHECK(client_session_control_);
 327   DCHECK(client_stub_);
 328
 329   // The worker thread is created with base::MessageLoop::TYPE_IO because
 330   // the PeerConnection performs some port allocation operations on this thread
 331   // that require it. See crbug.com/404013.
 332   base::Thread::Options options(base::MessageLoop::TYPE_IO, 0);
 333   worker_thread_.StartWithOptions(options);
 334   worker_task_runner_ = worker_thread_.task_runner();
 335 }
 336
 337 bool CastExtensionSession::ParseAndSetRemoteDescription(
 338     base::DictionaryValue* message) {
 339   DCHECK(peer_connection_.get() != NULL);
 340
 341   base::DictionaryValue* message_data;
 342   if (!message->GetDictionary(kTopLevelData, &message_data)) {
 343     LOG(ERROR) << "Invalid Cast Extension Message (missing data).";
 344     return false;
 345   }
 346
 347   std::string webrtc_type;
 348   if (!message_data->GetString(kWebRtcSessionDescType, &webrtc_type)) {
 349     LOG(ERROR)
 350         << "Invalid Cast Extension Message (missing webrtc type header).";
 351     return false;
 352   }
 353
 354   std::string sdp;
 355   if (!message_data->GetString(kWebRtcSessionDescSDP, &sdp)) {
 356     LOG(ERROR) << "Invalid Cast Extension Message (missing webrtc sdp header).";
 357     return false;
 358   }
 359
 360   webrtc::SdpParseError error;
 361   webrtc::SessionDescriptionInterface* session_description(
 362       webrtc::CreateSessionDescription(webrtc_type, sdp, &error));
 363
 364   if (!session_description) {
 365     LOG(ERROR) << "Invalid Cast Extension Message (could not parse sdp).";
 366     VLOG(1) << "SdpParseError was: " << error.description;
 367     return false;
 368   }
 369
 370   peer_connection_->SetRemoteDescription(
 371       CastSetSessionDescriptionObserver::Create(), session_description);
 372   return true;
 373 }
 374
 375 bool CastExtensionSession::ParseAndAddICECandidate(
 376     base::DictionaryValue* message) {
 377   DCHECK(peer_connection_.get() != NULL);
 378
 379   base::DictionaryValue* message_data;
 380   if (!message->GetDictionary(kTopLevelData, &message_data)) {
 381     LOG(ERROR) << "Invalid Cast Extension Message (missing data).";
 382     return false;
 383   }
 384
 385   std::string candidate_str;
 386   std::string sdp_mid;
 387   int sdp_mlineindex = 0;
 388   if (!message_data->GetString(kWebRtcSDPMid, &sdp_mid) ||
 389       !message_data->GetInteger(kWebRtcSDPMLineIndex, &sdp_mlineindex) ||
 390       !message_data->GetString(kWebRtcCandidate, &candidate_str)) {
 391     LOG(ERROR) << "Invalid Cast Extension Message (could not parse).";
 392     return false;
 393   }
 394
 395   rtc::scoped_ptr<webrtc::IceCandidateInterface> candidate(
 396       webrtc::CreateIceCandidate(sdp_mid, sdp_mlineindex, candidate_str));
 397   if (!candidate.get()) {
 398     LOG(ERROR)
 399         << "Invalid Cast Extension Message (could not create candidate).";
 400     return false;
 401   }
 402
 403   if (!peer_connection_->AddIceCandidate(candidate.get())) {
 404     LOG(ERROR) << "Failed to apply received ICE Candidate to PeerConnection.";
 405     return false;
 406   }
 407
 408   VLOG(1) << "Received and Added ICE Candidate: " << candidate_str;
 409
 410   return true;
 411 }
 412
 413 bool CastExtensionSession::SendMessageToClient(const std::string& subject,
 414                                                const std::string& data) {
 415   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 416
 417   if (client_stub_ == NULL) {
 418     LOG(ERROR) << "No Client Stub. Cannot send message to client.";
 419     return false;
 420   }
 421
 422   base::DictionaryValue message_dict;
 423   message_dict.SetString(kTopLevelSubject, subject);
 424   message_dict.SetString(kTopLevelData, data);
 425   std::string message_json;
 426
 427   if (!base::JSONWriter::Write(&message_dict, &message_json)) {
 428     LOG(ERROR) << "Failed to serialize JSON message.";
 429     return false;
 430   }
 431
 432   protocol::ExtensionMessage message;
 433   message.set_type(kExtensionMessageType);
 434   message.set_data(message_json);
 435   client_stub_->DeliverHostMessage(message);
 436   return true;
 437 }
 438
 439 void CastExtensionSession::EnsureTaskAndSetSend(rtc::Thread** ptr,
 440                                                 base::WaitableEvent* event) {
 441   jingle_glue::JingleThreadWrapper::EnsureForCurrentMessageLoop();
 442   jingle_glue::JingleThreadWrapper::current()->set_send_allowed(true);
 443   *ptr = jingle_glue::JingleThreadWrapper::current();
 444
 445   if (event != NULL) {
 446     event->Signal();
 447   }
 448 }
 449
 450 bool CastExtensionSession::WrapTasksAndSave() {
 451   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 452
 453   EnsureTaskAndSetSend(&signaling_thread_wrapper_);
 454   if (signaling_thread_wrapper_ == NULL)
 455     return false;
 456
 457   base::WaitableEvent wrap_worker_thread_event(true, false);
 458   worker_task_runner_->PostTask(
 459       FROM_HERE,
 460       base::Bind(&CastExtensionSession::EnsureTaskAndSetSend,
 461                  base::Unretained(this),
 462                  &worker_thread_wrapper_,
 463                  &wrap_worker_thread_event));
 464   wrap_worker_thread_event.Wait();
 465
 466   return (worker_thread_wrapper_ != NULL);
 467 }
 468
 469 bool CastExtensionSession::InitializePeerConnection() {
 470   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 471   DCHECK(!peer_conn_factory_);
 472   DCHECK(!peer_connection_);
 473   DCHECK(worker_thread_wrapper_ != NULL);
 474   DCHECK(signaling_thread_wrapper_ != NULL);
 475
 476   peer_conn_factory_ = webrtc::CreatePeerConnectionFactory(
 477       worker_thread_wrapper_, signaling_thread_wrapper_, NULL, NULL, NULL);
 478
 479   if (!peer_conn_factory_.get()) {
 480     CleanupPeerConnection();
 481     return false;
 482   }
 483
 484   VLOG(1) << "Created PeerConnectionFactory successfully.";
 485
 486   webrtc::PeerConnectionInterface::IceServers servers;
 487   webrtc::PeerConnectionInterface::IceServer server;
 488   server.uri = kDefaultStunURI;
 489   servers.push_back(server);
 490   webrtc::PeerConnectionInterface::RTCConfiguration rtc_config;
 491   rtc_config.servers = servers;
 492
 493   // DTLS-SRTP is the preferred encryption method. If set to kValueFalse, the
 494   // peer connection uses SDES. Disabling SDES as well will cause the peer
 495   // connection to fail to connect.
 496   // Note: For protection and unprotection of SRTP packets, the libjingle
 497   // ENABLE_EXTERNAL_AUTH flag must not be set.
 498   webrtc::FakeConstraints constraints;
 499   constraints.AddMandatory(webrtc::MediaConstraintsInterface::kEnableDtlsSrtp,
 500                            webrtc::MediaConstraintsInterface::kValueTrue);
 501
 502   rtc::scoped_refptr<webrtc::PortAllocatorFactoryInterface>
 503       port_allocator_factory = ChromiumPortAllocatorFactory::Create(
 504           network_settings_, url_request_context_getter_);
 505
 506   peer_connection_ = peer_conn_factory_->CreatePeerConnection(
 507       rtc_config, &constraints, port_allocator_factory, NULL, this);
 508
 509   if (!peer_connection_.get()) {
 510     CleanupPeerConnection();
 511     return false;
 512   }
 513
 514   VLOG(1) << "Created PeerConnection successfully.";
 515
 516   create_session_desc_observer_ =
 517       CastCreateSessionDescriptionObserver::Create(this);
 518
 519   // Send a test message to the client. Then, notify the client to start
 520   // webrtc offer/answer negotiation.
 521   if (!SendMessageToClient(kSubjectTest, "Hello, client.") ||
 522       !SendMessageToClient(kSubjectReady, "Host ready to receive offers.")) {
 523     LOG(ERROR) << "Failed to send messages to client.";
 524     return false;
 525   }
 526
 527   return true;
 528 }
 529
 530 bool CastExtensionSession::SetupVideoStream(
 531     scoped_ptr<webrtc::DesktopCapturer> desktop_capturer) {
 532   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 533   DCHECK(desktop_capturer);
 534
 535   if (stream_) {
 536     VLOG(1) << "Already added MediaStream. Aborting Setup.";
 537     return false;
 538   }
 539
 540   scoped_ptr<CastVideoCapturerAdapter> cast_video_capturer_adapter(
 541       new CastVideoCapturerAdapter(desktop_capturer.Pass()));
 542
 543   // Set video stream constraints.
 544   webrtc::FakeConstraints video_constraints;
 545   video_constraints.AddMandatory(
 546       webrtc::MediaConstraintsInterface::kMinFrameRate, kMinFramesPerSecond);
 547
 548   rtc::scoped_refptr<webrtc::VideoTrackInterface> video_track =
 549       peer_conn_factory_->CreateVideoTrack(
 550           kVideoLabel,
 551           peer_conn_factory_->CreateVideoSource(
 552               cast_video_capturer_adapter.release(), &video_constraints));
 553
 554   stream_ = peer_conn_factory_->CreateLocalMediaStream(kStreamLabel);
 555
 556   if (!stream_->AddTrack(video_track) ||
 557       !peer_connection_->AddStream(stream_, NULL)) {
 558     return false;
 559   }
 560
 561   VLOG(1) << "Setup video stream successfully.";
 562
 563   return true;
 564 }
 565
 566 void CastExtensionSession::PollPeerConnectionStats() {
 567   if (!connection_active()) {
 568     VLOG(1) << "Cannot poll stats while PeerConnection is inactive.";
 569   }
 570   rtc::scoped_refptr<webrtc::MediaStreamTrackInterface> video_track =
 571       stream_->FindVideoTrack(kVideoLabel);
 572   peer_connection_->GetStats(
 573       stats_observer_,
 574       video_track.release(),
 575       webrtc::PeerConnectionInterface::kStatsOutputLevelStandard);
 576 }
 577
 578 void CastExtensionSession::CleanupPeerConnection() {
 579   peer_connection_->Close();
 580   peer_connection_ = NULL;
 581   stream_ = NULL;
 582   peer_conn_factory_ = NULL;
 583   worker_thread_.Stop();
 584 }
 585
 586 bool CastExtensionSession::connection_active() const {
 587   return peer_connection_.get() != NULL;
 588 }
 589
 590 // webrtc::PeerConnectionObserver implementation -------------------------------
 591
 592 void CastExtensionSession::OnError() {
 593   VLOG(1) << "PeerConnectionObserver: an error occurred.";
 594 }
 595
 596 void CastExtensionSession::OnSignalingChange(
 597     webrtc::PeerConnectionInterface::SignalingState new_state) {
 598   VLOG(1) << "PeerConnectionObserver: SignalingState changed to:" << new_state;
 599 }
 600
 601 void CastExtensionSession::OnStateChange(
 602     webrtc::PeerConnectionObserver::StateType state_changed) {
 603   VLOG(1) << "PeerConnectionObserver: StateType changed to: " << state_changed;
 604 }
 605
 606 void CastExtensionSession::OnAddStream(webrtc::MediaStreamInterface* stream) {
 607   VLOG(1) << "PeerConnectionObserver: stream added: " << stream->label();
 608 }
 609
 610 void CastExtensionSession::OnRemoveStream(
 611     webrtc::MediaStreamInterface* stream) {
 612   VLOG(1) << "PeerConnectionObserver: stream removed: " << stream->label();
 613 }
 614
 615 void CastExtensionSession::OnDataChannel(
 616     webrtc::DataChannelInterface* data_channel) {
 617   VLOG(1) << "PeerConnectionObserver: data channel: " << data_channel->label();
 618 }
 619
 620 void CastExtensionSession::OnRenegotiationNeeded() {
 621   VLOG(1) << "PeerConnectionObserver: renegotiation needed.";
 622 }
 623
 624 void CastExtensionSession::OnIceConnectionChange(
 625     webrtc::PeerConnectionInterface::IceConnectionState new_state) {
 626   VLOG(1) << "PeerConnectionObserver: IceConnectionState changed to: "
 627           << new_state;
 628
 629   // TODO(aiguha): Maybe start timer only if enabled by command-line flag or
 630   // at a particular verbosity level.
 631   if (!stats_polling_timer_.IsRunning() &&
 632       new_state == webrtc::PeerConnectionInterface::kIceConnectionConnected) {
 633     stats_polling_timer_.Start(
 634         FROM_HERE,
 635         base::TimeDelta::FromSeconds(kStatsLogIntervalSec),
 636         this,
 637         &CastExtensionSession::PollPeerConnectionStats);
 638   }
 639 }
 640
 641 void CastExtensionSession::OnIceGatheringChange(
 642     webrtc::PeerConnectionInterface::IceGatheringState new_state) {
 643   VLOG(1) << "PeerConnectionObserver: IceGatheringState changed to: "
 644           << new_state;
 645 }
 646
 647 void CastExtensionSession::OnIceComplete() {
 648   VLOG(1) << "PeerConnectionObserver: all ICE candidates found.";
 649 }
 650
 651 void CastExtensionSession::OnIceCandidate(
 652     const webrtc::IceCandidateInterface* candidate) {
 653   std::string candidate_str;
 654   if (!candidate->ToString(&candidate_str)) {
 655     LOG(ERROR) << "PeerConnectionObserver: failed to serialize candidate.";
 656     return;
 657   }
 658   scoped_ptr<base::DictionaryValue> json(new base::DictionaryValue());
 659   json->SetString(kWebRtcSDPMid, candidate->sdp_mid());
 660   json->SetInteger(kWebRtcSDPMLineIndex, candidate->sdp_mline_index());
 661   json->SetString(kWebRtcCandidate, candidate_str);
 662   std::string json_str;
 663   if (!base::JSONWriter::Write(json.get(), &json_str)) {
 664     LOG(ERROR) << "Failed to serialize candidate message.";
 665     return;
 666   }
 667   SendMessageToClient(kSubjectNewCandidate, json_str);
 668 }
 669
 670 }  // namespace remoting