Adds trunk/talk folder of revision 359 from libjingles google code to
trunk/talk


git-svn-id: http://webrtc.googlecode.com/svn/trunk@4318 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/talk/session/media/channel.cc b/talk/session/media/channel.cc
new file mode 100644
index 0000000..1048cdf
--- /dev/null
+++ b/talk/session/media/channel.cc
@@ -0,0 +1,2704 @@
+/*
+ * libjingle
+ * Copyright 2004 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.
+ */
+
+#include "talk/session/media/channel.h"
+
+#include "talk/base/buffer.h"
+#include "talk/base/byteorder.h"
+#include "talk/base/common.h"
+#include "talk/base/logging.h"
+#include "talk/media/base/rtputils.h"
+#include "talk/p2p/base/transportchannel.h"
+#include "talk/session/media/channelmanager.h"
+#include "talk/session/media/mediamessages.h"
+#include "talk/session/media/rtcpmuxfilter.h"
+#include "talk/session/media/typingmonitor.h"
+
+
+namespace cricket {
+
+enum {
+  MSG_ENABLE = 1,
+  MSG_DISABLE,
+  MSG_MUTESTREAM,
+  MSG_ISSTREAMMUTED,
+  MSG_SETREMOTECONTENT,
+  MSG_SETLOCALCONTENT,
+  MSG_EARLYMEDIATIMEOUT,
+  MSG_CANINSERTDTMF,
+  MSG_INSERTDTMF,
+  MSG_GETSTATS,
+  MSG_SETRENDERER,
+  MSG_ADDRECVSTREAM,
+  MSG_REMOVERECVSTREAM,
+  MSG_SETRINGBACKTONE,
+  MSG_PLAYRINGBACKTONE,
+  MSG_SETMAXSENDBANDWIDTH,
+  MSG_ADDSCREENCAST,
+  MSG_REMOVESCREENCAST,
+  MSG_SENDINTRAFRAME,
+  MSG_REQUESTINTRAFRAME,
+  MSG_SCREENCASTWINDOWEVENT,
+  MSG_RTPPACKET,
+  MSG_RTCPPACKET,
+  MSG_CHANNEL_ERROR,
+  MSG_SETCHANNELOPTIONS,
+  MSG_SCALEVOLUME,
+  MSG_HANDLEVIEWREQUEST,
+  MSG_READYTOSENDDATA,
+  MSG_SENDDATA,
+  MSG_DATARECEIVED,
+  MSG_SETCAPTURER,
+  MSG_ISSCREENCASTING,
+  MSG_SCREENCASTFPS,
+  MSG_SETSCREENCASTFACTORY,
+  MSG_FIRSTPACKETRECEIVED,
+  MSG_SESSION_ERROR,
+};
+
+// Value specified in RFC 5764.
+static const char kDtlsSrtpExporterLabel[] = "EXTRACTOR-dtls_srtp";
+
+static const int kAgcMinus10db = -10;
+
+// TODO(hellner): use the device manager for creation of screen capturers when
+// the cl enabling it has landed.
+class NullScreenCapturerFactory : public VideoChannel::ScreenCapturerFactory {
+ public:
+  VideoCapturer* CreateScreenCapturer(const ScreencastId& window) {
+    return NULL;
+  }
+};
+
+
+VideoChannel::ScreenCapturerFactory* CreateScreenCapturerFactory() {
+  return new NullScreenCapturerFactory();
+}
+
+struct SetContentData : public talk_base::MessageData {
+  SetContentData(const MediaContentDescription* content, ContentAction action)
+      : content(content),
+        action(action),
+        result(false) {
+  }
+  const MediaContentDescription* content;
+  ContentAction action;
+  bool result;
+};
+
+struct SetBandwidthData : public talk_base::MessageData {
+  explicit SetBandwidthData(int value) : value(value), result(false) {}
+  int value;
+  bool result;
+};
+
+struct SetRingbackToneMessageData : public talk_base::MessageData {
+  SetRingbackToneMessageData(const void* b, int l)
+      : buf(b),
+        len(l),
+        result(false) {
+  }
+  const void* buf;
+  int len;
+  bool result;
+};
+
+struct PlayRingbackToneMessageData : public talk_base::MessageData {
+  PlayRingbackToneMessageData(uint32 s, bool p, bool l)
+      : ssrc(s),
+        play(p),
+        loop(l),
+        result(false) {
+  }
+  uint32 ssrc;
+  bool play;
+  bool loop;
+  bool result;
+};
+typedef talk_base::TypedMessageData<bool> BoolMessageData;
+struct DtmfMessageData : public talk_base::MessageData {
+  DtmfMessageData(uint32 ssrc, int event, int duration, int flags)
+      : ssrc(ssrc),
+        event(event),
+        duration(duration),
+        flags(flags),
+        result(false) {
+  }
+  uint32 ssrc;
+  int event;
+  int duration;
+  int flags;
+  bool result;
+};
+struct ScaleVolumeMessageData : public talk_base::MessageData {
+  ScaleVolumeMessageData(uint32 s, double l, double r)
+      : ssrc(s),
+        left(l),
+        right(r),
+        result(false) {
+  }
+  uint32 ssrc;
+  double left;
+  double right;
+  bool result;
+};
+
+struct VoiceStatsMessageData : public talk_base::MessageData {
+  explicit VoiceStatsMessageData(VoiceMediaInfo* stats)
+      : result(false),
+        stats(stats) {
+  }
+  bool result;
+  VoiceMediaInfo* stats;
+};
+
+struct VideoStatsMessageData : public talk_base::MessageData {
+  explicit VideoStatsMessageData(VideoMediaInfo* stats)
+      : result(false),
+        stats(stats) {
+  }
+  bool result;
+  VideoMediaInfo* stats;
+};
+
+struct PacketMessageData : public talk_base::MessageData {
+  talk_base::Buffer packet;
+};
+
+struct AudioRenderMessageData: public talk_base::MessageData {
+  AudioRenderMessageData(uint32 s, AudioRenderer* r)
+      : ssrc(s), renderer(r), result(false) {}
+  uint32 ssrc;
+  AudioRenderer* renderer;
+  bool result;
+};
+
+struct VideoRenderMessageData : public talk_base::MessageData {
+  VideoRenderMessageData(uint32 s, VideoRenderer* r) : ssrc(s), renderer(r) {}
+  uint32 ssrc;
+  VideoRenderer* renderer;
+};
+
+struct AddScreencastMessageData : public talk_base::MessageData {
+  AddScreencastMessageData(uint32 s, const ScreencastId& id)
+      : ssrc(s),
+        window_id(id),
+        result(NULL) {
+  }
+  uint32 ssrc;
+  ScreencastId window_id;
+  VideoCapturer* result;
+};
+
+struct RemoveScreencastMessageData : public talk_base::MessageData {
+  explicit RemoveScreencastMessageData(uint32 s) : ssrc(s), result(false) {}
+  uint32 ssrc;
+  bool result;
+};
+
+struct ScreencastEventMessageData : public talk_base::MessageData {
+  ScreencastEventMessageData(uint32 s, talk_base::WindowEvent we)
+      : ssrc(s),
+        event(we) {
+  }
+  uint32 ssrc;
+  talk_base::WindowEvent event;
+};
+
+struct ViewRequestMessageData : public talk_base::MessageData {
+  explicit ViewRequestMessageData(const ViewRequest& r)
+      : request(r),
+        result(false) {
+  }
+  ViewRequest request;
+  bool result;
+};
+
+struct VoiceChannelErrorMessageData : public talk_base::MessageData {
+  VoiceChannelErrorMessageData(uint32 in_ssrc,
+                               VoiceMediaChannel::Error in_error)
+      : ssrc(in_ssrc),
+        error(in_error) {
+  }
+  uint32 ssrc;
+  VoiceMediaChannel::Error error;
+};
+
+struct VideoChannelErrorMessageData : public talk_base::MessageData {
+  VideoChannelErrorMessageData(uint32 in_ssrc,
+                               VideoMediaChannel::Error in_error)
+      : ssrc(in_ssrc),
+        error(in_error) {
+  }
+  uint32 ssrc;
+  VideoMediaChannel::Error error;
+};
+
+struct DataChannelErrorMessageData : public talk_base::MessageData {
+  DataChannelErrorMessageData(uint32 in_ssrc,
+                              DataMediaChannel::Error in_error)
+      : ssrc(in_ssrc),
+        error(in_error) {}
+  uint32 ssrc;
+  DataMediaChannel::Error error;
+};
+
+struct SessionErrorMessageData : public talk_base::MessageData {
+  explicit SessionErrorMessageData(cricket::BaseSession::Error error)
+      : error_(error) {}
+
+  BaseSession::Error error_;
+};
+
+struct SsrcMessageData : public talk_base::MessageData {
+  explicit SsrcMessageData(uint32 ssrc) : ssrc(ssrc), result(false) {}
+  uint32 ssrc;
+  bool result;
+};
+
+struct StreamMessageData : public talk_base::MessageData {
+  explicit StreamMessageData(const StreamParams& in_sp)
+      : sp(in_sp),
+        result(false) {
+  }
+  StreamParams sp;
+  bool result;
+};
+
+struct MuteStreamData : public talk_base::MessageData {
+  MuteStreamData(uint32 ssrc, bool mute)
+      : ssrc(ssrc), mute(mute), result(false) {}
+  uint32 ssrc;
+  bool mute;
+  bool result;
+};
+
+struct AudioOptionsMessageData : public talk_base::MessageData {
+  explicit AudioOptionsMessageData(const AudioOptions& options)
+      : options(options),
+        result(false) {
+  }
+  AudioOptions options;
+  bool result;
+};
+
+struct VideoOptionsMessageData : public talk_base::MessageData {
+  explicit VideoOptionsMessageData(const VideoOptions& options)
+      : options(options),
+        result(false) {
+  }
+  VideoOptions options;
+  bool result;
+};
+
+struct SetCapturerMessageData : public talk_base::MessageData {
+  SetCapturerMessageData(uint32 s, VideoCapturer* c)
+      : ssrc(s),
+        capturer(c),
+        result(false) {
+  }
+  uint32 ssrc;
+  VideoCapturer* capturer;
+  bool result;
+};
+
+struct IsScreencastingMessageData : public talk_base::MessageData {
+  IsScreencastingMessageData()
+      : result(false) {
+  }
+  bool result;
+};
+
+struct ScreencastFpsMessageData : public talk_base::MessageData {
+  explicit ScreencastFpsMessageData(uint32 s)
+      : ssrc(s), result(0) {
+  }
+  uint32 ssrc;
+  int result;
+};
+
+struct SetScreenCaptureFactoryMessageData : public talk_base::MessageData {
+  explicit SetScreenCaptureFactoryMessageData(
+      VideoChannel::ScreenCapturerFactory* f)
+      : screencapture_factory(f) {
+  }
+  VideoChannel::ScreenCapturerFactory* screencapture_factory;
+};
+
+static const char* PacketType(bool rtcp) {
+  return (!rtcp) ? "RTP" : "RTCP";
+}
+
+static bool ValidPacket(bool rtcp, const talk_base::Buffer* packet) {
+  // Check the packet size. We could check the header too if needed.
+  return (packet &&
+      packet->length() >= (!rtcp ? kMinRtpPacketLen : kMinRtcpPacketLen) &&
+      packet->length() <= kMaxRtpPacketLen);
+}
+
+static bool IsReceiveContentDirection(MediaContentDirection direction) {
+  return direction == MD_SENDRECV || direction == MD_RECVONLY;
+}
+
+static bool IsSendContentDirection(MediaContentDirection direction) {
+  return direction == MD_SENDRECV || direction == MD_SENDONLY;
+}
+
+static const MediaContentDescription* GetContentDescription(
+    const ContentInfo* cinfo) {
+  if (cinfo == NULL)
+    return NULL;
+  return static_cast<const MediaContentDescription*>(cinfo->description);
+}
+
+BaseChannel::BaseChannel(talk_base::Thread* thread,
+                         MediaEngineInterface* media_engine,
+                         MediaChannel* media_channel, BaseSession* session,
+                         const std::string& content_name, bool rtcp)
+    : worker_thread_(thread),
+      media_engine_(media_engine),
+      session_(session),
+      media_channel_(media_channel),
+      content_name_(content_name),
+      rtcp_(rtcp),
+      transport_channel_(NULL),
+      rtcp_transport_channel_(NULL),
+      enabled_(false),
+      writable_(false),
+      rtp_ready_to_send_(false),
+      rtcp_ready_to_send_(false),
+      optimistic_data_send_(false),
+      was_ever_writable_(false),
+      local_content_direction_(MD_INACTIVE),
+      remote_content_direction_(MD_INACTIVE),
+      has_received_packet_(false),
+      dtls_keyed_(false),
+      secure_required_(false) {
+  ASSERT(worker_thread_ == talk_base::Thread::Current());
+  LOG(LS_INFO) << "Created channel for " << content_name;
+}
+
+BaseChannel::~BaseChannel() {
+  ASSERT(worker_thread_ == talk_base::Thread::Current());
+  StopConnectionMonitor();
+  FlushRtcpMessages();  // Send any outstanding RTCP packets.
+  Clear();  // eats any outstanding messages or packets
+  // We must destroy the media channel before the transport channel, otherwise
+  // the media channel may try to send on the dead transport channel. NULLing
+  // is not an effective strategy since the sends will come on another thread.
+  delete media_channel_;
+  set_rtcp_transport_channel(NULL);
+  if (transport_channel_ != NULL)
+    session_->DestroyChannel(content_name_, transport_channel_->component());
+  LOG(LS_INFO) << "Destroyed channel";
+}
+
+bool BaseChannel::Init(TransportChannel* transport_channel,
+                       TransportChannel* rtcp_transport_channel) {
+  if (transport_channel == NULL) {
+    return false;
+  }
+  if (rtcp() && rtcp_transport_channel == NULL) {
+    return false;
+  }
+  transport_channel_ = transport_channel;
+
+  if (!SetDtlsSrtpCiphers(transport_channel_, false)) {
+    return false;
+  }
+
+  media_channel_->SetInterface(this);
+  transport_channel_->SignalWritableState.connect(
+      this, &BaseChannel::OnWritableState);
+  transport_channel_->SignalReadPacket.connect(
+      this, &BaseChannel::OnChannelRead);
+  transport_channel_->SignalReadyToSend.connect(
+      this, &BaseChannel::OnReadyToSend);
+
+  session_->SignalNewLocalDescription.connect(
+      this, &BaseChannel::OnNewLocalDescription);
+  session_->SignalNewRemoteDescription.connect(
+      this, &BaseChannel::OnNewRemoteDescription);
+
+  set_rtcp_transport_channel(rtcp_transport_channel);
+  return true;
+}
+
+// Can be called from thread other than worker thread
+bool BaseChannel::Enable(bool enable) {
+  Send(enable ? MSG_ENABLE : MSG_DISABLE);
+  return true;
+}
+
+// Can be called from thread other than worker thread
+bool BaseChannel::MuteStream(uint32 ssrc, bool mute) {
+  MuteStreamData data(ssrc, mute);
+  Send(MSG_MUTESTREAM, &data);
+  return data.result;
+}
+
+bool BaseChannel::IsStreamMuted(uint32 ssrc) {
+  SsrcMessageData data(ssrc);
+  Send(MSG_ISSTREAMMUTED, &data);
+  return data.result;
+}
+
+bool BaseChannel::AddRecvStream(const StreamParams& sp) {
+  StreamMessageData data(sp);
+  Send(MSG_ADDRECVSTREAM, &data);
+  return data.result;
+}
+
+bool BaseChannel::RemoveRecvStream(uint32 ssrc) {
+  SsrcMessageData data(ssrc);
+  Send(MSG_REMOVERECVSTREAM, &data);
+  return data.result;
+}
+
+bool BaseChannel::SetLocalContent(const MediaContentDescription* content,
+                                  ContentAction action) {
+  SetContentData data(content, action);
+  Send(MSG_SETLOCALCONTENT, &data);
+  return data.result;
+}
+
+bool BaseChannel::SetRemoteContent(const MediaContentDescription* content,
+                                   ContentAction action) {
+  SetContentData data(content, action);
+  Send(MSG_SETREMOTECONTENT, &data);
+  return data.result;
+}
+
+bool BaseChannel::SetMaxSendBandwidth(int max_bandwidth) {
+  SetBandwidthData data(max_bandwidth);
+  Send(MSG_SETMAXSENDBANDWIDTH, &data);
+  return data.result;
+}
+
+void BaseChannel::StartConnectionMonitor(int cms) {
+  socket_monitor_.reset(new SocketMonitor(transport_channel_,
+                                          worker_thread(),
+                                          talk_base::Thread::Current()));
+  socket_monitor_->SignalUpdate.connect(
+      this, &BaseChannel::OnConnectionMonitorUpdate);
+  socket_monitor_->Start(cms);
+}
+
+void BaseChannel::StopConnectionMonitor() {
+  if (socket_monitor_) {
+    socket_monitor_->Stop();
+    socket_monitor_.reset();
+  }
+}
+
+void BaseChannel::set_rtcp_transport_channel(TransportChannel* channel) {
+  if (rtcp_transport_channel_ != channel) {
+    if (rtcp_transport_channel_) {
+      session_->DestroyChannel(
+          content_name_, rtcp_transport_channel_->component());
+    }
+    rtcp_transport_channel_ = channel;
+    if (rtcp_transport_channel_) {
+      // TODO(juberti): Propagate this error code
+      VERIFY(SetDtlsSrtpCiphers(rtcp_transport_channel_, true));
+      rtcp_transport_channel_->SignalWritableState.connect(
+          this, &BaseChannel::OnWritableState);
+      rtcp_transport_channel_->SignalReadPacket.connect(
+          this, &BaseChannel::OnChannelRead);
+      rtcp_transport_channel_->SignalReadyToSend.connect(
+          this, &BaseChannel::OnReadyToSend);
+    }
+  }
+}
+
+bool BaseChannel::IsReadyToReceive() const {
+  // Receive data if we are enabled and have local content,
+  return enabled() && IsReceiveContentDirection(local_content_direction_);
+}
+
+bool BaseChannel::IsReadyToSend() const {
+  // Send outgoing data if we are enabled, have local and remote content,
+  // and we have had some form of connectivity.
+  return enabled() &&
+         IsReceiveContentDirection(remote_content_direction_) &&
+         IsSendContentDirection(local_content_direction_) &&
+         was_ever_writable();
+}
+
+bool BaseChannel::SendPacket(talk_base::Buffer* packet) {
+  return SendPacket(false, packet);
+}
+
+bool BaseChannel::SendRtcp(talk_base::Buffer* packet) {
+  return SendPacket(true, packet);
+}
+
+int BaseChannel::SetOption(SocketType type, talk_base::Socket::Option opt,
+                           int value) {
+  switch (type) {
+    case ST_RTP: return transport_channel_->SetOption(opt, value);
+    case ST_RTCP: return rtcp_transport_channel_->SetOption(opt, value);
+    default: return -1;
+  }
+}
+
+void BaseChannel::OnWritableState(TransportChannel* channel) {
+  ASSERT(channel == transport_channel_ || channel == rtcp_transport_channel_);
+  if (transport_channel_->writable()
+      && (!rtcp_transport_channel_ || rtcp_transport_channel_->writable())) {
+    ChannelWritable_w();
+  } else {
+    ChannelNotWritable_w();
+  }
+}
+
+void BaseChannel::OnChannelRead(TransportChannel* channel,
+                                const char* data, size_t len, int flags) {
+  // OnChannelRead gets called from P2PSocket; now pass data to MediaEngine
+  ASSERT(worker_thread_ == talk_base::Thread::Current());
+
+  // When using RTCP multiplexing we might get RTCP packets on the RTP
+  // transport. We feed RTP traffic into the demuxer to determine if it is RTCP.
+  bool rtcp = PacketIsRtcp(channel, data, len);
+  talk_base::Buffer packet(data, len);
+  HandlePacket(rtcp, &packet);
+}
+
+void BaseChannel::OnReadyToSend(TransportChannel* channel) {
+  SetReadyToSend(channel, true);
+}
+
+void BaseChannel::SetReadyToSend(TransportChannel* channel, bool ready) {
+  ASSERT(channel == transport_channel_ || channel == rtcp_transport_channel_);
+  if (channel == transport_channel_) {
+    rtp_ready_to_send_ = ready;
+  }
+  if (channel == rtcp_transport_channel_) {
+    rtcp_ready_to_send_ = ready;
+  }
+
+  if (!ready) {
+    // Notify the MediaChannel when either rtp or rtcp channel can't send.
+    media_channel_->OnReadyToSend(false);
+  } else if (rtp_ready_to_send_ &&
+             // In the case of rtcp mux |rtcp_transport_channel_| will be null.
+             (rtcp_ready_to_send_ || !rtcp_transport_channel_)) {
+    // Notify the MediaChannel when both rtp and rtcp channel can send.
+    media_channel_->OnReadyToSend(true);
+  }
+}
+
+bool BaseChannel::PacketIsRtcp(const TransportChannel* channel,
+                               const char* data, size_t len) {
+  return (channel == rtcp_transport_channel_ ||
+          rtcp_mux_filter_.DemuxRtcp(data, len));
+}
+
+bool BaseChannel::SendPacket(bool rtcp, talk_base::Buffer* packet) {
+  // Unless we're sending optimistically, we only allow packets through when we
+  // are completely writable.
+  if (!optimistic_data_send_ && !writable_) {
+    return false;
+  }
+
+  // SendPacket gets called from MediaEngine, typically on an encoder thread.
+  // If the thread is not our worker thread, we will post to our worker
+  // so that the real work happens on our worker. This avoids us having to
+  // synchronize access to all the pieces of the send path, including
+  // SRTP and the inner workings of the transport channels.
+  // The only downside is that we can't return a proper failure code if
+  // needed. Since UDP is unreliable anyway, this should be a non-issue.
+  if (talk_base::Thread::Current() != worker_thread_) {
+    // Avoid a copy by transferring the ownership of the packet data.
+    int message_id = (!rtcp) ? MSG_RTPPACKET : MSG_RTCPPACKET;
+    PacketMessageData* data = new PacketMessageData;
+    packet->TransferTo(&data->packet);
+    worker_thread_->Post(this, message_id, data);
+    return true;
+  }
+
+  // Now that we are on the correct thread, ensure we have a place to send this
+  // packet before doing anything. (We might get RTCP packets that we don't
+  // intend to send.) If we've negotiated RTCP mux, send RTCP over the RTP
+  // transport.
+  TransportChannel* channel = (!rtcp || rtcp_mux_filter_.IsActive()) ?
+      transport_channel_ : rtcp_transport_channel_;
+  if (!channel || (!optimistic_data_send_ && !channel->writable())) {
+    return false;
+  }
+
+  // Protect ourselves against crazy data.
+  if (!ValidPacket(rtcp, packet)) {
+    LOG(LS_ERROR) << "Dropping outgoing " << content_name_ << " "
+                  << PacketType(rtcp) << " packet: wrong size="
+                  << packet->length();
+    return false;
+  }
+
+  // Signal to the media sink before protecting the packet.
+  {
+    talk_base::CritScope cs(&signal_send_packet_cs_);
+    SignalSendPacketPreCrypto(packet->data(), packet->length(), rtcp);
+  }
+
+  // Protect if needed.
+  if (srtp_filter_.IsActive()) {
+    bool res;
+    char* data = packet->data();
+    int len = packet->length();
+    if (!rtcp) {
+      res = srtp_filter_.ProtectRtp(data, len, packet->capacity(), &len);
+      if (!res) {
+        int seq_num = -1;
+        uint32 ssrc = 0;
+        GetRtpSeqNum(data, len, &seq_num);
+        GetRtpSsrc(data, len, &ssrc);
+        LOG(LS_ERROR) << "Failed to protect " << content_name_
+                      << " RTP packet: size=" << len
+                      << ", seqnum=" << seq_num << ", SSRC=" << ssrc;
+        return false;
+      }
+    } else {
+      res = srtp_filter_.ProtectRtcp(data, len, packet->capacity(), &len);
+      if (!res) {
+        int type = -1;
+        GetRtcpType(data, len, &type);
+        LOG(LS_ERROR) << "Failed to protect " << content_name_
+                      << " RTCP packet: size=" << len << ", type=" << type;
+        return false;
+      }
+    }
+
+    // Update the length of the packet now that we've added the auth tag.
+    packet->SetLength(len);
+  } else if (secure_required_) {
+    // This is a double check for something that supposedly can't happen.
+    LOG(LS_ERROR) << "Can't send outgoing " << PacketType(rtcp)
+                  << " packet when SRTP is inactive and crypto is required";
+
+    ASSERT(false);
+    return false;
+  }
+
+  // Signal to the media sink after protecting the packet.
+  {
+    talk_base::CritScope cs(&signal_send_packet_cs_);
+    SignalSendPacketPostCrypto(packet->data(), packet->length(), rtcp);
+  }
+
+  // Bon voyage.
+  int ret = channel->SendPacket(packet->data(), packet->length(),
+      (secure() && secure_dtls()) ? PF_SRTP_BYPASS : 0);
+  if (ret != static_cast<int>(packet->length())) {
+    if (channel->GetError() == EWOULDBLOCK) {
+      LOG(LS_WARNING) << "Got EWOULDBLOCK from socket.";
+      SetReadyToSend(channel, false);
+    }
+    return false;
+  }
+  return true;
+}
+
+bool BaseChannel::WantsPacket(bool rtcp, talk_base::Buffer* packet) {
+  // Protect ourselves against crazy data.
+  if (!ValidPacket(rtcp, packet)) {
+    LOG(LS_ERROR) << "Dropping incoming " << content_name_ << " "
+                  << PacketType(rtcp) << " packet: wrong size="
+                  << packet->length();
+    return false;
+  }
+  // If this channel is suppose to handle RTP data, that is determined by
+  // checking against ssrc filter. This is necessary to do it here to avoid
+  // double decryption.
+  if (ssrc_filter_.IsActive() &&
+      !ssrc_filter_.DemuxPacket(packet->data(), packet->length(), rtcp)) {
+    return false;
+  }
+
+  return true;
+}
+
+void BaseChannel::HandlePacket(bool rtcp, talk_base::Buffer* packet) {
+  if (!WantsPacket(rtcp, packet)) {
+    return;
+  }
+
+  if (!has_received_packet_) {
+    has_received_packet_ = true;
+    signaling_thread()->Post(this, MSG_FIRSTPACKETRECEIVED);
+  }
+
+  // Signal to the media sink before unprotecting the packet.
+  {
+    talk_base::CritScope cs(&signal_recv_packet_cs_);
+    SignalRecvPacketPostCrypto(packet->data(), packet->length(), rtcp);
+  }
+
+  // Unprotect the packet, if needed.
+  if (srtp_filter_.IsActive()) {
+    char* data = packet->data();
+    int len = packet->length();
+    bool res;
+    if (!rtcp) {
+      res = srtp_filter_.UnprotectRtp(data, len, &len);
+      if (!res) {
+        int seq_num = -1;
+        uint32 ssrc = 0;
+        GetRtpSeqNum(data, len, &seq_num);
+        GetRtpSsrc(data, len, &ssrc);
+        LOG(LS_ERROR) << "Failed to unprotect " << content_name_
+                      << " RTP packet: size=" << len
+                      << ", seqnum=" << seq_num << ", SSRC=" << ssrc;
+        return;
+      }
+    } else {
+      res = srtp_filter_.UnprotectRtcp(data, len, &len);
+      if (!res) {
+        int type = -1;
+        GetRtcpType(data, len, &type);
+        LOG(LS_ERROR) << "Failed to unprotect " << content_name_
+                      << " RTCP packet: size=" << len << ", type=" << type;
+        return;
+      }
+    }
+
+    packet->SetLength(len);
+  } else if (secure_required_) {
+    // Our session description indicates that SRTP is required, but we got a
+    // packet before our SRTP filter is active. This means either that
+    // a) we got SRTP packets before we received the SDES keys, in which case
+    //    we can't decrypt it anyway, or
+    // b) we got SRTP packets before DTLS completed on both the RTP and RTCP
+    //    channels, so we haven't yet extracted keys, even if DTLS did complete
+    //    on the channel that the packets are being sent on. It's really good
+    //    practice to wait for both RTP and RTCP to be good to go before sending
+    //    media, to prevent weird failure modes, so it's fine for us to just eat
+    //    packets here. This is all sidestepped if RTCP mux is used anyway.
+    LOG(LS_WARNING) << "Can't process incoming " << PacketType(rtcp)
+                    << " packet when SRTP is inactive and crypto is required";
+    return;
+  }
+
+  // Signal to the media sink after unprotecting the packet.
+  {
+    talk_base::CritScope cs(&signal_recv_packet_cs_);
+    SignalRecvPacketPreCrypto(packet->data(), packet->length(), rtcp);
+  }
+
+  // Push it down to the media channel.
+  if (!rtcp) {
+    media_channel_->OnPacketReceived(packet);
+  } else {
+    media_channel_->OnRtcpReceived(packet);
+  }
+}
+
+void BaseChannel::OnNewLocalDescription(
+    BaseSession* session, ContentAction action) {
+  const ContentInfo* content_info =
+      GetFirstContent(session->local_description());
+  const MediaContentDescription* content_desc =
+      GetContentDescription(content_info);
+  if (content_desc && content_info && !content_info->rejected &&
+      !SetLocalContent(content_desc, action)) {
+    LOG(LS_ERROR) << "Failure in SetLocalContent with action " << action;
+    session->SetError(BaseSession::ERROR_CONTENT);
+  }
+}
+
+void BaseChannel::OnNewRemoteDescription(
+    BaseSession* session, ContentAction action) {
+  const ContentInfo* content_info =
+      GetFirstContent(session->remote_description());
+  const MediaContentDescription* content_desc =
+      GetContentDescription(content_info);
+  if (content_desc && content_info && !content_info->rejected &&
+      !SetRemoteContent(content_desc, action)) {
+    LOG(LS_ERROR) << "Failure in SetRemoteContent with  action " << action;
+    session->SetError(BaseSession::ERROR_CONTENT);
+  }
+}
+
+void BaseChannel::EnableMedia_w() {
+  ASSERT(worker_thread_ == talk_base::Thread::Current());
+  if (enabled_)
+    return;
+
+  LOG(LS_INFO) << "Channel enabled";
+  enabled_ = true;
+  ChangeState();
+}
+
+void BaseChannel::DisableMedia_w() {
+  ASSERT(worker_thread_ == talk_base::Thread::Current());
+  if (!enabled_)
+    return;
+
+  LOG(LS_INFO) << "Channel disabled";
+  enabled_ = false;
+  ChangeState();
+}
+
+bool BaseChannel::MuteStream_w(uint32 ssrc, bool mute) {
+  ASSERT(worker_thread_ == talk_base::Thread::Current());
+  bool ret = media_channel()->MuteStream(ssrc, mute);
+  if (ret) {
+    if (mute)
+      muted_streams_.insert(ssrc);
+    else
+      muted_streams_.erase(ssrc);
+  }
+  return ret;
+}
+
+bool BaseChannel::IsStreamMuted_w(uint32 ssrc) {
+  ASSERT(worker_thread_ == talk_base::Thread::Current());
+  return muted_streams_.find(ssrc) != muted_streams_.end();
+}
+
+void BaseChannel::ChannelWritable_w() {
+  ASSERT(worker_thread_ == talk_base::Thread::Current());
+  if (writable_)
+    return;
+
+  LOG(LS_INFO) << "Channel socket writable ("
+               << transport_channel_->content_name() << ", "
+               << transport_channel_->component() << ")"
+               << (was_ever_writable_ ? "" : " for the first time");
+
+  std::vector<ConnectionInfo> infos;
+  transport_channel_->GetStats(&infos);
+  for (std::vector<ConnectionInfo>::const_iterator it = infos.begin();
+       it != infos.end(); ++it) {
+    if (it->best_connection) {
+      LOG(LS_INFO) << "Using " << it->local_candidate.ToSensitiveString()
+                   << "->" << it->remote_candidate.ToSensitiveString();
+      break;
+    }
+  }
+
+  // If we're doing DTLS-SRTP, now is the time.
+  if (!was_ever_writable_ && ShouldSetupDtlsSrtp()) {
+    if (!SetupDtlsSrtp(false)) {
+      LOG(LS_ERROR) << "Couldn't finish DTLS-SRTP on RTP channel";
+      SessionErrorMessageData data(BaseSession::ERROR_TRANSPORT);
+      // Sent synchronously.
+      signaling_thread()->Send(this, MSG_SESSION_ERROR, &data);
+      return;
+    }
+
+    if (rtcp_transport_channel_) {
+      if (!SetupDtlsSrtp(true)) {
+        LOG(LS_ERROR) << "Couldn't finish DTLS-SRTP on RTCP channel";
+        SessionErrorMessageData data(BaseSession::ERROR_TRANSPORT);
+        // Sent synchronously.
+        signaling_thread()->Send(this, MSG_SESSION_ERROR, &data);
+        return;
+      }
+    }
+  }
+
+  was_ever_writable_ = true;
+  writable_ = true;
+  ChangeState();
+}
+
+bool BaseChannel::SetDtlsSrtpCiphers(TransportChannel *tc, bool rtcp) {
+  std::vector<std::string> ciphers;
+  // We always use the default SRTP ciphers for RTCP, but we may use different
+  // ciphers for RTP depending on the media type.
+  if (!rtcp) {
+    GetSrtpCiphers(&ciphers);
+  } else {
+    GetSupportedDefaultCryptoSuites(&ciphers);
+  }
+  return tc->SetSrtpCiphers(ciphers);
+}
+
+bool BaseChannel::ShouldSetupDtlsSrtp() const {
+  return true;
+}
+
+// This function returns true if either DTLS-SRTP is not in use
+// *or* DTLS-SRTP is successfully set up.
+bool BaseChannel::SetupDtlsSrtp(bool rtcp_channel) {
+  bool ret = false;
+
+  TransportChannel *channel = rtcp_channel ?
+      rtcp_transport_channel_ : transport_channel_;
+
+  // No DTLS
+  if (!channel->IsDtlsActive())
+    return true;
+
+  std::string selected_cipher;
+
+  if (!channel->GetSrtpCipher(&selected_cipher)) {
+    LOG(LS_ERROR) << "No DTLS-SRTP selected cipher";
+    return false;
+  }
+
+  LOG(LS_INFO) << "Installing keys from DTLS-SRTP on "
+               << content_name() << " "
+               << PacketType(rtcp_channel);
+
+  // OK, we're now doing DTLS (RFC 5764)
+  std::vector<unsigned char> dtls_buffer(SRTP_MASTER_KEY_KEY_LEN * 2 +
+                                         SRTP_MASTER_KEY_SALT_LEN * 2);
+
+  // RFC 5705 exporter using the RFC 5764 parameters
+  if (!channel->ExportKeyingMaterial(
+          kDtlsSrtpExporterLabel,
+          NULL, 0, false,
+          &dtls_buffer[0], dtls_buffer.size())) {
+    LOG(LS_WARNING) << "DTLS-SRTP key export failed";
+    ASSERT(false);  // This should never happen
+    return false;
+  }
+
+  // Sync up the keys with the DTLS-SRTP interface
+  std::vector<unsigned char> client_write_key(SRTP_MASTER_KEY_KEY_LEN +
+    SRTP_MASTER_KEY_SALT_LEN);
+  std::vector<unsigned char> server_write_key(SRTP_MASTER_KEY_KEY_LEN +
+    SRTP_MASTER_KEY_SALT_LEN);
+  size_t offset = 0;
+  memcpy(&client_write_key[0], &dtls_buffer[offset],
+    SRTP_MASTER_KEY_KEY_LEN);
+  offset += SRTP_MASTER_KEY_KEY_LEN;
+  memcpy(&server_write_key[0], &dtls_buffer[offset],
+    SRTP_MASTER_KEY_KEY_LEN);
+  offset += SRTP_MASTER_KEY_KEY_LEN;
+  memcpy(&client_write_key[SRTP_MASTER_KEY_KEY_LEN],
+    &dtls_buffer[offset], SRTP_MASTER_KEY_SALT_LEN);
+  offset += SRTP_MASTER_KEY_SALT_LEN;
+  memcpy(&server_write_key[SRTP_MASTER_KEY_KEY_LEN],
+    &dtls_buffer[offset], SRTP_MASTER_KEY_SALT_LEN);
+
+  std::vector<unsigned char> *send_key, *recv_key;
+
+  if (channel->GetRole() == ROLE_CONTROLLING) {
+    send_key = &server_write_key;
+    recv_key = &client_write_key;
+  } else {
+    send_key = &client_write_key;
+    recv_key = &server_write_key;
+  }
+
+  if (rtcp_channel) {
+    ret = srtp_filter_.SetRtcpParams(selected_cipher,
+      &(*send_key)[0], send_key->size(),
+      selected_cipher,
+      &(*recv_key)[0], recv_key->size());
+  } else {
+    ret = srtp_filter_.SetRtpParams(selected_cipher,
+      &(*send_key)[0], send_key->size(),
+      selected_cipher,
+      &(*recv_key)[0], recv_key->size());
+  }
+
+  if (!ret)
+    LOG(LS_WARNING) << "DTLS-SRTP key installation failed";
+  else
+    dtls_keyed_ = true;
+
+  return ret;
+}
+
+void BaseChannel::ChannelNotWritable_w() {
+  ASSERT(worker_thread_ == talk_base::Thread::Current());
+  if (!writable_)
+    return;
+
+  LOG(LS_INFO) << "Channel socket not writable ("
+               << transport_channel_->content_name() << ", "
+               << transport_channel_->component() << ")";
+  writable_ = false;
+  ChangeState();
+}
+
+// Sets the maximum video bandwidth for automatic bandwidth adjustment.
+bool BaseChannel::SetMaxSendBandwidth_w(int max_bandwidth) {
+  return media_channel()->SetSendBandwidth(true, max_bandwidth);
+}
+
+bool BaseChannel::SetSrtp_w(const std::vector<CryptoParams>& cryptos,
+                            ContentAction action, ContentSource src) {
+  bool ret = false;
+  switch (action) {
+    case CA_OFFER:
+      ret = srtp_filter_.SetOffer(cryptos, src);
+      break;
+    case CA_PRANSWER:
+      // If we're doing DTLS-SRTP, we don't want to update the filter
+      // with an answer, because we already have SRTP parameters.
+      if (transport_channel_->IsDtlsActive()) {
+        LOG(LS_INFO) <<
+          "Ignoring SDES answer parameters because we are using DTLS-SRTP";
+        ret = true;
+      } else {
+        ret = srtp_filter_.SetProvisionalAnswer(cryptos, src);
+      }
+      break;
+    case CA_ANSWER:
+      // If we're doing DTLS-SRTP, we don't want to update the filter
+      // with an answer, because we already have SRTP parameters.
+      if (transport_channel_->IsDtlsActive()) {
+        LOG(LS_INFO) <<
+          "Ignoring SDES answer parameters because we are using DTLS-SRTP";
+        ret = true;
+      } else {
+        ret = srtp_filter_.SetAnswer(cryptos, src);
+      }
+      break;
+    case CA_UPDATE:
+      // no crypto params.
+      ret = true;
+      break;
+    default:
+      break;
+  }
+  return ret;
+}
+
+bool BaseChannel::SetRtcpMux_w(bool enable, ContentAction action,
+                               ContentSource src) {
+  bool ret = false;
+  switch (action) {
+    case CA_OFFER:
+      ret = rtcp_mux_filter_.SetOffer(enable, src);
+      break;
+    case CA_PRANSWER:
+      ret = rtcp_mux_filter_.SetProvisionalAnswer(enable, src);
+      break;
+    case CA_ANSWER:
+      ret = rtcp_mux_filter_.SetAnswer(enable, src);
+      if (ret && rtcp_mux_filter_.IsActive()) {
+        // We activated RTCP mux, close down the RTCP transport.
+        set_rtcp_transport_channel(NULL);
+      }
+      break;
+    case CA_UPDATE:
+      // No RTCP mux info.
+      ret = true;
+    default:
+      break;
+  }
+  // |rtcp_mux_filter_| can be active if |action| is CA_PRANSWER or
+  // CA_ANSWER, but we only want to tear down the RTCP transport channel if we
+  // received a final answer.
+  if (ret && rtcp_mux_filter_.IsActive()) {
+    // If the RTP transport is already writable, then so are we.
+    if (transport_channel_->writable()) {
+      ChannelWritable_w();
+    }
+  }
+
+  return ret;
+}
+
+bool BaseChannel::AddRecvStream_w(const StreamParams& sp) {
+  ASSERT(worker_thread() == talk_base::Thread::Current());
+  if (!media_channel()->AddRecvStream(sp))
+    return false;
+
+  return ssrc_filter_.AddStream(sp);
+}
+
+bool BaseChannel::RemoveRecvStream_w(uint32 ssrc) {
+  ASSERT(worker_thread() == talk_base::Thread::Current());
+  ssrc_filter_.RemoveStream(ssrc);
+  return media_channel()->RemoveRecvStream(ssrc);
+}
+
+bool BaseChannel::UpdateLocalStreams_w(const std::vector<StreamParams>& streams,
+                                       ContentAction action) {
+  if (!VERIFY(action == CA_OFFER || action == CA_ANSWER ||
+              action == CA_PRANSWER || action == CA_UPDATE))
+    return false;
+
+  // If this is an update, streams only contain streams that have changed.
+  if (action == CA_UPDATE) {
+    for (StreamParamsVec::const_iterator it = streams.begin();
+         it != streams.end(); ++it) {
+      StreamParams existing_stream;
+      bool stream_exist = GetStreamByIds(local_streams_, it->groupid,
+                                         it->id, &existing_stream);
+      if (!stream_exist && it->has_ssrcs()) {
+        if (media_channel()->AddSendStream(*it)) {
+          local_streams_.push_back(*it);
+          LOG(LS_INFO) << "Add send stream ssrc: " << it->first_ssrc();
+        } else {
+          LOG(LS_INFO) << "Failed to add send stream ssrc: "
+                       << it->first_ssrc();
+          return false;
+        }
+      } else if (stream_exist && !it->has_ssrcs()) {
+        if (!media_channel()->RemoveSendStream(existing_stream.first_ssrc())) {
+            LOG(LS_ERROR) << "Failed to remove send stream with ssrc "
+                          << it->first_ssrc() << ".";
+            return false;
+        }
+        RemoveStreamBySsrc(&local_streams_, existing_stream.first_ssrc());
+      } else {
+        LOG(LS_WARNING) << "Ignore unsupported stream update";
+      }
+    }
+    return true;
+  }
+  // Else streams are all the streams we want to send.
+
+  // Check for streams that have been removed.
+  bool ret = true;
+  for (StreamParamsVec::const_iterator it = local_streams_.begin();
+       it != local_streams_.end(); ++it) {
+    if (!GetStreamBySsrc(streams, it->first_ssrc(), NULL)) {
+      if (!media_channel()->RemoveSendStream(it->first_ssrc())) {
+        LOG(LS_ERROR) << "Failed to remove send stream with ssrc "
+                      << it->first_ssrc() << ".";
+        ret = false;
+      }
+    }
+  }
+  // Check for new streams.
+  for (StreamParamsVec::const_iterator it = streams.begin();
+       it != streams.end(); ++it) {
+    if (!GetStreamBySsrc(local_streams_, it->first_ssrc(), NULL)) {
+      if (media_channel()->AddSendStream(*it)) {
+        LOG(LS_INFO) << "Add send ssrc: " << it->ssrcs[0];
+      } else {
+        LOG(LS_INFO) << "Failed to add send stream ssrc: " << it->first_ssrc();
+        ret = false;
+      }
+    }
+  }
+  local_streams_ = streams;
+  return ret;
+}
+
+bool BaseChannel::UpdateRemoteStreams_w(
+    const std::vector<StreamParams>& streams,
+    ContentAction action) {
+  if (!VERIFY(action == CA_OFFER || action == CA_ANSWER ||
+              action == CA_PRANSWER || action == CA_UPDATE))
+    return false;
+
+  // If this is an update, streams only contain streams that have changed.
+  if (action == CA_UPDATE) {
+    for (StreamParamsVec::const_iterator it = streams.begin();
+         it != streams.end(); ++it) {
+      StreamParams existing_stream;
+      bool stream_exists = GetStreamByIds(remote_streams_, it->groupid,
+                                          it->id, &existing_stream);
+      if (!stream_exists && it->has_ssrcs()) {
+        if (AddRecvStream_w(*it)) {
+          remote_streams_.push_back(*it);
+          LOG(LS_INFO) << "Add remote stream ssrc: " << it->first_ssrc();
+        } else {
+          LOG(LS_INFO) << "Failed to add remote stream ssrc: "
+                       << it->first_ssrc();
+          return false;
+        }
+      } else if (stream_exists && !it->has_ssrcs()) {
+        if (!RemoveRecvStream_w(existing_stream.first_ssrc())) {
+            LOG(LS_ERROR) << "Failed to remove remote stream with ssrc "
+                          << it->first_ssrc() << ".";
+            return false;
+        }
+        RemoveStreamBySsrc(&remote_streams_, existing_stream.first_ssrc());
+      } else {
+        LOG(LS_WARNING) << "Ignore unsupported stream update."
+                        << " Stream exists? " << stream_exists
+                        << " existing stream = " << existing_stream.ToString()
+                        << " new stream = " << it->ToString();
+      }
+    }
+    return true;
+  }
+  // Else streams are all the streams we want to receive.
+
+  // Check for streams that have been removed.
+  bool ret = true;
+  for (StreamParamsVec::const_iterator it = remote_streams_.begin();
+       it != remote_streams_.end(); ++it) {
+    if (!GetStreamBySsrc(streams, it->first_ssrc(), NULL)) {
+      if (!RemoveRecvStream_w(it->first_ssrc())) {
+        LOG(LS_ERROR) << "Failed to remove remote stream with ssrc "
+                      << it->first_ssrc() << ".";
+        ret = false;
+      }
+    }
+  }
+  // Check for new streams.
+  for (StreamParamsVec::const_iterator it = streams.begin();
+      it != streams.end(); ++it) {
+    if (!GetStreamBySsrc(remote_streams_, it->first_ssrc(), NULL)) {
+      if (AddRecvStream_w(*it)) {
+        LOG(LS_INFO) << "Add remote ssrc: " << it->ssrcs[0];
+      } else {
+        LOG(LS_INFO) << "Failed to add remote stream ssrc: "
+                     << it->first_ssrc();
+        ret = false;
+      }
+    }
+  }
+  remote_streams_ = streams;
+  return ret;
+}
+
+bool BaseChannel::SetBaseLocalContent_w(const MediaContentDescription* content,
+                                        ContentAction action) {
+  // Cache secure_required_ for belt and suspenders check on SendPacket
+  secure_required_ = content->crypto_required();
+  bool ret = UpdateLocalStreams_w(content->streams(), action);
+  // Set local SRTP parameters (what we will encrypt with).
+  ret &= SetSrtp_w(content->cryptos(), action, CS_LOCAL);
+  // Set local RTCP mux parameters.
+  ret &= SetRtcpMux_w(content->rtcp_mux(), action, CS_LOCAL);
+  // Set local RTP header extensions.
+  if (content->rtp_header_extensions_set()) {
+    ret &= media_channel()->SetRecvRtpHeaderExtensions(
+        content->rtp_header_extensions());
+  }
+  set_local_content_direction(content->direction());
+  return ret;
+}
+
+bool BaseChannel::SetBaseRemoteContent_w(const MediaContentDescription* content,
+                                         ContentAction action) {
+  bool ret = UpdateRemoteStreams_w(content->streams(), action);
+  // Set remote SRTP parameters (what the other side will encrypt with).
+  ret &= SetSrtp_w(content->cryptos(), action, CS_REMOTE);
+  // Set remote RTCP mux parameters.
+  ret &= SetRtcpMux_w(content->rtcp_mux(), action, CS_REMOTE);
+  // Set remote RTP header extensions.
+  if (content->rtp_header_extensions_set()) {
+    ret &= media_channel()->SetSendRtpHeaderExtensions(
+        content->rtp_header_extensions());
+  }
+  if (content->bandwidth() != kAutoBandwidth) {
+    ret &= media_channel()->SetSendBandwidth(false, content->bandwidth());
+  }
+  set_remote_content_direction(content->direction());
+  return ret;
+}
+
+void BaseChannel::OnMessage(talk_base::Message *pmsg) {
+  switch (pmsg->message_id) {
+    case MSG_ENABLE:
+      EnableMedia_w();
+      break;
+    case MSG_DISABLE:
+      DisableMedia_w();
+      break;
+    case MSG_MUTESTREAM: {
+      MuteStreamData* data = static_cast<MuteStreamData*>(pmsg->pdata);
+      data->result = MuteStream_w(data->ssrc, data->mute);
+      break;
+    }
+    case MSG_ISSTREAMMUTED: {
+      SsrcMessageData* data = static_cast<SsrcMessageData*>(pmsg->pdata);
+      data->result = IsStreamMuted_w(data->ssrc);
+      break;
+    }
+    case MSG_SETLOCALCONTENT: {
+      SetContentData* data = static_cast<SetContentData*>(pmsg->pdata);
+      data->result = SetLocalContent_w(data->content, data->action);
+      break;
+    }
+    case MSG_SETREMOTECONTENT: {
+      SetContentData* data = static_cast<SetContentData*>(pmsg->pdata);
+      data->result = SetRemoteContent_w(data->content, data->action);
+      break;
+    }
+    case MSG_ADDRECVSTREAM: {
+      StreamMessageData* data = static_cast<StreamMessageData*>(pmsg->pdata);
+      data->result = AddRecvStream_w(data->sp);
+      break;
+    }
+    case MSG_REMOVERECVSTREAM: {
+      SsrcMessageData* data = static_cast<SsrcMessageData*>(pmsg->pdata);
+      data->result = RemoveRecvStream_w(data->ssrc);
+      break;
+    }
+    case MSG_SETMAXSENDBANDWIDTH: {
+      SetBandwidthData* data = static_cast<SetBandwidthData*>(pmsg->pdata);
+      data->result = SetMaxSendBandwidth_w(data->value);
+      break;
+    }
+
+    case MSG_RTPPACKET:
+    case MSG_RTCPPACKET: {
+      PacketMessageData* data = static_cast<PacketMessageData*>(pmsg->pdata);
+      SendPacket(pmsg->message_id == MSG_RTCPPACKET, &data->packet);
+      delete data;  // because it is Posted
+      break;
+    }
+    case MSG_FIRSTPACKETRECEIVED: {
+      SignalFirstPacketReceived(this);
+      break;
+    }
+    case MSG_SESSION_ERROR: {
+      SessionErrorMessageData* data = static_cast<SessionErrorMessageData*>
+          (pmsg->pdata);
+      session_->SetError(data->error_);
+      break;
+    }
+  }
+}
+
+void BaseChannel::Send(uint32 id, talk_base::MessageData *pdata) {
+  worker_thread_->Send(this, id, pdata);
+}
+
+void BaseChannel::Post(uint32 id, talk_base::MessageData *pdata) {
+  worker_thread_->Post(this, id, pdata);
+}
+
+void BaseChannel::PostDelayed(int cmsDelay, uint32 id,
+                              talk_base::MessageData *pdata) {
+  worker_thread_->PostDelayed(cmsDelay, this, id, pdata);
+}
+
+void BaseChannel::Clear(uint32 id, talk_base::MessageList* removed) {
+  worker_thread_->Clear(this, id, removed);
+}
+
+void BaseChannel::FlushRtcpMessages() {
+  // Flush all remaining RTCP messages. This should only be called in
+  // destructor.
+  ASSERT(talk_base::Thread::Current() == worker_thread_);
+  talk_base::MessageList rtcp_messages;
+  Clear(MSG_RTCPPACKET, &rtcp_messages);
+  for (talk_base::MessageList::iterator it = rtcp_messages.begin();
+       it != rtcp_messages.end(); ++it) {
+    Send(MSG_RTCPPACKET, it->pdata);
+  }
+}
+
+VoiceChannel::VoiceChannel(talk_base::Thread* thread,
+                           MediaEngineInterface* media_engine,
+                           VoiceMediaChannel* media_channel,
+                           BaseSession* session,
+                           const std::string& content_name,
+                           bool rtcp)
+    : BaseChannel(thread, media_engine, media_channel, session, content_name,
+                  rtcp),
+      received_media_(false) {
+}
+
+VoiceChannel::~VoiceChannel() {
+  StopAudioMonitor();
+  StopMediaMonitor();
+  // this can't be done in the base class, since it calls a virtual
+  DisableMedia_w();
+}
+
+bool VoiceChannel::Init() {
+  TransportChannel* rtcp_channel = rtcp() ? session()->CreateChannel(
+      content_name(), "rtcp", ICE_CANDIDATE_COMPONENT_RTCP) : NULL;
+  if (!BaseChannel::Init(session()->CreateChannel(
+          content_name(), "rtp", ICE_CANDIDATE_COMPONENT_RTP),
+          rtcp_channel)) {
+    return false;
+  }
+  media_channel()->SignalMediaError.connect(
+      this, &VoiceChannel::OnVoiceChannelError);
+  srtp_filter()->SignalSrtpError.connect(
+      this, &VoiceChannel::OnSrtpError);
+  return true;
+}
+
+bool VoiceChannel::SetRenderer(uint32 ssrc, AudioRenderer* renderer) {
+  AudioRenderMessageData data(ssrc, renderer);
+  Send(MSG_SETRENDERER, &data);
+  return data.result;
+}
+
+bool VoiceChannel::SetRingbackTone(const void* buf, int len) {
+  SetRingbackToneMessageData data(buf, len);
+  Send(MSG_SETRINGBACKTONE, &data);
+  return data.result;
+}
+
+// TODO(juberti): Handle early media the right way. We should get an explicit
+// ringing message telling us to start playing local ringback, which we cancel
+// if any early media actually arrives. For now, we do the opposite, which is
+// to wait 1 second for early media, and start playing local ringback if none
+// arrives.
+void VoiceChannel::SetEarlyMedia(bool enable) {
+  if (enable) {
+    // Start the early media timeout
+    PostDelayed(kEarlyMediaTimeout, MSG_EARLYMEDIATIMEOUT);
+  } else {
+    // Stop the timeout if currently going.
+    Clear(MSG_EARLYMEDIATIMEOUT);
+  }
+}
+
+bool VoiceChannel::PlayRingbackTone(uint32 ssrc, bool play, bool loop) {
+  PlayRingbackToneMessageData data(ssrc, play, loop);
+  Send(MSG_PLAYRINGBACKTONE, &data);
+  return data.result;
+}
+
+bool VoiceChannel::PressDTMF(int digit, bool playout) {
+  int flags = DF_SEND;
+  if (playout) {
+    flags |= DF_PLAY;
+  }
+  int duration_ms = 160;
+  return InsertDtmf(0, digit, duration_ms, flags);
+}
+
+bool VoiceChannel::CanInsertDtmf() {
+  BoolMessageData data(false);
+  Send(MSG_CANINSERTDTMF, &data);
+  return data.data();
+}
+
+bool VoiceChannel::InsertDtmf(uint32 ssrc, int event_code, int duration,
+                              int flags) {
+  DtmfMessageData data(ssrc, event_code, duration, flags);
+  Send(MSG_INSERTDTMF, &data);
+  return data.result;
+}
+
+bool VoiceChannel::SetOutputScaling(uint32 ssrc, double left, double right) {
+  ScaleVolumeMessageData data(ssrc, left, right);
+  Send(MSG_SCALEVOLUME, &data);
+  return data.result;
+}
+bool VoiceChannel::GetStats(VoiceMediaInfo* stats) {
+  VoiceStatsMessageData data(stats);
+  Send(MSG_GETSTATS, &data);
+  return data.result;
+}
+
+void VoiceChannel::StartMediaMonitor(int cms) {
+  media_monitor_.reset(new VoiceMediaMonitor(media_channel(), worker_thread(),
+      talk_base::Thread::Current()));
+  media_monitor_->SignalUpdate.connect(
+      this, &VoiceChannel::OnMediaMonitorUpdate);
+  media_monitor_->Start(cms);
+}
+
+void VoiceChannel::StopMediaMonitor() {
+  if (media_monitor_) {
+    media_monitor_->Stop();
+    media_monitor_->SignalUpdate.disconnect(this);
+    media_monitor_.reset();
+  }
+}
+
+void VoiceChannel::StartAudioMonitor(int cms) {
+  audio_monitor_.reset(new AudioMonitor(this, talk_base::Thread::Current()));
+  audio_monitor_
+    ->SignalUpdate.connect(this, &VoiceChannel::OnAudioMonitorUpdate);
+  audio_monitor_->Start(cms);
+}
+
+void VoiceChannel::StopAudioMonitor() {
+  if (audio_monitor_) {
+    audio_monitor_->Stop();
+    audio_monitor_.reset();
+  }
+}
+
+bool VoiceChannel::IsAudioMonitorRunning() const {
+  return (audio_monitor_.get() != NULL);
+}
+
+void VoiceChannel::StartTypingMonitor(const TypingMonitorOptions& settings) {
+  typing_monitor_.reset(new TypingMonitor(this, worker_thread(), settings));
+  SignalAutoMuted.repeat(typing_monitor_->SignalMuted);
+}
+
+void VoiceChannel::StopTypingMonitor() {
+  typing_monitor_.reset();
+}
+
+bool VoiceChannel::IsTypingMonitorRunning() const {
+  return typing_monitor_;
+}
+
+bool VoiceChannel::MuteStream_w(uint32 ssrc, bool mute) {
+  bool ret = BaseChannel::MuteStream_w(ssrc, mute);
+  if (typing_monitor_ && mute)
+    typing_monitor_->OnChannelMuted();
+  return ret;
+}
+
+int VoiceChannel::GetInputLevel_w() {
+  return media_engine()->GetInputLevel();
+}
+
+int VoiceChannel::GetOutputLevel_w() {
+  return media_channel()->GetOutputLevel();
+}
+
+void VoiceChannel::GetActiveStreams_w(AudioInfo::StreamList* actives) {
+  media_channel()->GetActiveStreams(actives);
+}
+
+void VoiceChannel::OnChannelRead(TransportChannel* channel,
+                                 const char* data, size_t len, int flags) {
+  BaseChannel::OnChannelRead(channel, data, len, flags);
+
+  // Set a flag when we've received an RTP packet. If we're waiting for early
+  // media, this will disable the timeout.
+  if (!received_media_ && !PacketIsRtcp(channel, data, len)) {
+    received_media_ = true;
+  }
+}
+
+void VoiceChannel::ChangeState() {
+  // Render incoming data if we're the active call, and we have the local
+  // content. We receive data on the default channel and multiplexed streams.
+  bool recv = IsReadyToReceive();
+  if (!media_channel()->SetPlayout(recv)) {
+    SendLastMediaError();
+  }
+
+  // Send outgoing data if we're the active call, we have the remote content,
+  // and we have had some form of connectivity.
+  bool send = IsReadyToSend();
+  SendFlags send_flag = send ? SEND_MICROPHONE : SEND_NOTHING;
+  if (!media_channel()->SetSend(send_flag)) {
+    LOG(LS_ERROR) << "Failed to SetSend " << send_flag << " on voice channel";
+    SendLastMediaError();
+  }
+
+  LOG(LS_INFO) << "Changing voice state, recv=" << recv << " send=" << send;
+}
+
+const ContentInfo* VoiceChannel::GetFirstContent(
+    const SessionDescription* sdesc) {
+  return GetFirstAudioContent(sdesc);
+}
+
+bool VoiceChannel::SetLocalContent_w(const MediaContentDescription* content,
+                                     ContentAction action) {
+  ASSERT(worker_thread() == talk_base::Thread::Current());
+  LOG(LS_INFO) << "Setting local voice description";
+
+  const AudioContentDescription* audio =
+      static_cast<const AudioContentDescription*>(content);
+  ASSERT(audio != NULL);
+  if (!audio) return false;
+
+  bool ret = SetBaseLocalContent_w(content, action);
+  // Set local audio codecs (what we want to receive).
+  // TODO(whyuan): Change action != CA_UPDATE to !audio->partial() when partial
+  // is set properly.
+  if (action != CA_UPDATE || audio->has_codecs()) {
+    ret &= media_channel()->SetRecvCodecs(audio->codecs());
+  }
+
+  // If everything worked, see if we can start receiving.
+  if (ret) {
+    ChangeState();
+  } else {
+    LOG(LS_WARNING) << "Failed to set local voice description";
+  }
+  return ret;
+}
+
+bool VoiceChannel::SetRemoteContent_w(const MediaContentDescription* content,
+                                      ContentAction action) {
+  ASSERT(worker_thread() == talk_base::Thread::Current());
+  LOG(LS_INFO) << "Setting remote voice description";
+
+  const AudioContentDescription* audio =
+      static_cast<const AudioContentDescription*>(content);
+  ASSERT(audio != NULL);
+  if (!audio) return false;
+
+  bool ret = true;
+  // Set remote video codecs (what the other side wants to receive).
+  if (action != CA_UPDATE || audio->has_codecs()) {
+    ret &= media_channel()->SetSendCodecs(audio->codecs());
+  }
+
+  ret &= SetBaseRemoteContent_w(content, action);
+
+  if (action != CA_UPDATE) {
+    // Tweak our audio processing settings, if needed.
+    AudioOptions audio_options;
+    if (!media_channel()->GetOptions(&audio_options)) {
+      LOG(LS_WARNING) << "Can not set audio options from on remote content.";
+    } else {
+      if (audio->conference_mode()) {
+        audio_options.conference_mode.Set(true);
+      }
+      if (audio->agc_minus_10db()) {
+        audio_options.adjust_agc_delta.Set(kAgcMinus10db);
+      }
+      if (!media_channel()->SetOptions(audio_options)) {
+        // Log an error on failure, but don't abort the call.
+        LOG(LS_ERROR) << "Failed to set voice channel options";
+      }
+    }
+  }
+
+  // If everything worked, see if we can start sending.
+  if (ret) {
+    ChangeState();
+  } else {
+    LOG(LS_WARNING) << "Failed to set remote voice description";
+  }
+  return ret;
+}
+
+bool VoiceChannel::SetRingbackTone_w(const void* buf, int len) {
+  ASSERT(worker_thread() == talk_base::Thread::Current());
+  return media_channel()->SetRingbackTone(static_cast<const char*>(buf), len);
+}
+
+bool VoiceChannel::PlayRingbackTone_w(uint32 ssrc, bool play, bool loop) {
+  ASSERT(worker_thread() == talk_base::Thread::Current());
+  if (play) {
+    LOG(LS_INFO) << "Playing ringback tone, loop=" << loop;
+  } else {
+    LOG(LS_INFO) << "Stopping ringback tone";
+  }
+  return media_channel()->PlayRingbackTone(ssrc, play, loop);
+}
+
+void VoiceChannel::HandleEarlyMediaTimeout() {
+  // This occurs on the main thread, not the worker thread.
+  if (!received_media_) {
+    LOG(LS_INFO) << "No early media received before timeout";
+    SignalEarlyMediaTimeout(this);
+  }
+}
+
+bool VoiceChannel::CanInsertDtmf_w() {
+  return media_channel()->CanInsertDtmf();
+}
+
+bool VoiceChannel::InsertDtmf_w(uint32 ssrc, int event, int duration,
+                                int flags) {
+  if (!enabled()) {
+    return false;
+  }
+
+  return media_channel()->InsertDtmf(ssrc, event, duration, flags);
+}
+
+bool VoiceChannel::SetOutputScaling_w(uint32 ssrc, double left, double right) {
+  return media_channel()->SetOutputScaling(ssrc, left, right);
+}
+
+bool VoiceChannel::GetStats_w(VoiceMediaInfo* stats) {
+  return media_channel()->GetStats(stats);
+}
+
+bool VoiceChannel::SetChannelOptions(const AudioOptions& options) {
+  AudioOptionsMessageData data(options);
+  Send(MSG_SETCHANNELOPTIONS, &data);
+  return data.result;
+}
+
+bool VoiceChannel::SetChannelOptions_w(const AudioOptions& options) {
+  return media_channel()->SetOptions(options);
+}
+
+bool VoiceChannel::SetRenderer_w(uint32 ssrc, AudioRenderer* renderer) {
+  return media_channel()->SetRenderer(ssrc, renderer);
+}
+
+void VoiceChannel::OnMessage(talk_base::Message *pmsg) {
+  switch (pmsg->message_id) {
+    case MSG_SETRINGBACKTONE: {
+      SetRingbackToneMessageData* data =
+          static_cast<SetRingbackToneMessageData*>(pmsg->pdata);
+      data->result = SetRingbackTone_w(data->buf, data->len);
+      break;
+    }
+    case MSG_PLAYRINGBACKTONE: {
+      PlayRingbackToneMessageData* data =
+          static_cast<PlayRingbackToneMessageData*>(pmsg->pdata);
+      data->result = PlayRingbackTone_w(data->ssrc, data->play, data->loop);
+      break;
+    }
+    case MSG_EARLYMEDIATIMEOUT:
+      HandleEarlyMediaTimeout();
+      break;
+    case MSG_CANINSERTDTMF: {
+      BoolMessageData* data =
+          static_cast<BoolMessageData*>(pmsg->pdata);
+      data->data() = CanInsertDtmf_w();
+      break;
+    }
+    case MSG_INSERTDTMF: {
+      DtmfMessageData* data =
+          static_cast<DtmfMessageData*>(pmsg->pdata);
+      data->result = InsertDtmf_w(data->ssrc, data->event, data->duration,
+                                  data->flags);
+      break;
+    }
+    case MSG_SCALEVOLUME: {
+      ScaleVolumeMessageData* data =
+          static_cast<ScaleVolumeMessageData*>(pmsg->pdata);
+      data->result = SetOutputScaling_w(data->ssrc, data->left, data->right);
+      break;
+    }
+    case MSG_GETSTATS: {
+      VoiceStatsMessageData* data =
+          static_cast<VoiceStatsMessageData*>(pmsg->pdata);
+      data->result = GetStats_w(data->stats);
+      break;
+    }
+    case MSG_CHANNEL_ERROR: {
+      VoiceChannelErrorMessageData* data =
+          static_cast<VoiceChannelErrorMessageData*>(pmsg->pdata);
+      SignalMediaError(this, data->ssrc, data->error);
+      delete data;
+      break;
+    }
+    case MSG_SETCHANNELOPTIONS: {
+      AudioOptionsMessageData* data =
+          static_cast<AudioOptionsMessageData*>(pmsg->pdata);
+      data->result = SetChannelOptions_w(data->options);
+      break;
+    }
+    case MSG_SETRENDERER: {
+      AudioRenderMessageData* data =
+          static_cast<AudioRenderMessageData*>(pmsg->pdata);
+      data->result = SetRenderer_w(data->ssrc, data->renderer);
+      break;
+    }
+    default:
+      BaseChannel::OnMessage(pmsg);
+      break;
+  }
+}
+
+void VoiceChannel::OnConnectionMonitorUpdate(
+    SocketMonitor* monitor, const std::vector<ConnectionInfo>& infos) {
+  SignalConnectionMonitor(this, infos);
+}
+
+void VoiceChannel::OnMediaMonitorUpdate(
+    VoiceMediaChannel* media_channel, const VoiceMediaInfo& info) {
+  ASSERT(media_channel == this->media_channel());
+  SignalMediaMonitor(this, info);
+}
+
+void VoiceChannel::OnAudioMonitorUpdate(AudioMonitor* monitor,
+                                        const AudioInfo& info) {
+  SignalAudioMonitor(this, info);
+}
+
+void VoiceChannel::OnVoiceChannelError(
+    uint32 ssrc, VoiceMediaChannel::Error err) {
+  VoiceChannelErrorMessageData* data = new VoiceChannelErrorMessageData(
+      ssrc, err);
+  signaling_thread()->Post(this, MSG_CHANNEL_ERROR, data);
+}
+
+void VoiceChannel::OnSrtpError(uint32 ssrc, SrtpFilter::Mode mode,
+                               SrtpFilter::Error error) {
+  switch (error) {
+    case SrtpFilter::ERROR_FAIL:
+      OnVoiceChannelError(ssrc, (mode == SrtpFilter::PROTECT) ?
+                          VoiceMediaChannel::ERROR_REC_SRTP_ERROR :
+                          VoiceMediaChannel::ERROR_PLAY_SRTP_ERROR);
+      break;
+    case SrtpFilter::ERROR_AUTH:
+      OnVoiceChannelError(ssrc, (mode == SrtpFilter::PROTECT) ?
+                          VoiceMediaChannel::ERROR_REC_SRTP_AUTH_FAILED :
+                          VoiceMediaChannel::ERROR_PLAY_SRTP_AUTH_FAILED);
+      break;
+    case SrtpFilter::ERROR_REPLAY:
+      // Only receving channel should have this error.
+      ASSERT(mode == SrtpFilter::UNPROTECT);
+      OnVoiceChannelError(ssrc, VoiceMediaChannel::ERROR_PLAY_SRTP_REPLAY);
+      break;
+    default:
+      break;
+  }
+}
+
+void VoiceChannel::GetSrtpCiphers(std::vector<std::string>* ciphers) const {
+  GetSupportedAudioCryptoSuites(ciphers);
+}
+
+VideoChannel::VideoChannel(talk_base::Thread* thread,
+                           MediaEngineInterface* media_engine,
+                           VideoMediaChannel* media_channel,
+                           BaseSession* session,
+                           const std::string& content_name,
+                           bool rtcp,
+                           VoiceChannel* voice_channel)
+    : BaseChannel(thread, media_engine, media_channel, session, content_name,
+                  rtcp),
+      voice_channel_(voice_channel),
+      renderer_(NULL),
+      screencapture_factory_(CreateScreenCapturerFactory()),
+      previous_we_(talk_base::WE_CLOSE) {
+}
+
+bool VideoChannel::Init() {
+  TransportChannel* rtcp_channel = rtcp() ? session()->CreateChannel(
+      content_name(), "video_rtcp", ICE_CANDIDATE_COMPONENT_RTCP) : NULL;
+  if (!BaseChannel::Init(session()->CreateChannel(
+          content_name(), "video_rtp", ICE_CANDIDATE_COMPONENT_RTP),
+          rtcp_channel)) {
+    return false;
+  }
+  media_channel()->SignalMediaError.connect(
+      this, &VideoChannel::OnVideoChannelError);
+  srtp_filter()->SignalSrtpError.connect(
+      this, &VideoChannel::OnSrtpError);
+  return true;
+}
+
+void VoiceChannel::SendLastMediaError() {
+  uint32 ssrc;
+  VoiceMediaChannel::Error error;
+  media_channel()->GetLastMediaError(&ssrc, &error);
+  SignalMediaError(this, ssrc, error);
+}
+
+VideoChannel::~VideoChannel() {
+  std::vector<uint32> screencast_ssrcs;
+  ScreencastMap::iterator iter;
+  while (!screencast_capturers_.empty()) {
+    if (!RemoveScreencast(screencast_capturers_.begin()->first)) {
+      LOG(LS_ERROR) << "Unable to delete screencast with ssrc "
+                    << screencast_capturers_.begin()->first;
+      ASSERT(false);
+      break;
+    }
+  }
+
+  StopMediaMonitor();
+  // this can't be done in the base class, since it calls a virtual
+  DisableMedia_w();
+}
+
+bool VideoChannel::SetRenderer(uint32 ssrc, VideoRenderer* renderer) {
+  VideoRenderMessageData data(ssrc, renderer);
+  Send(MSG_SETRENDERER, &data);
+  return true;
+}
+
+bool VideoChannel::ApplyViewRequest(const ViewRequest& request) {
+  ViewRequestMessageData data(request);
+  Send(MSG_HANDLEVIEWREQUEST, &data);
+  return data.result;
+}
+
+VideoCapturer* VideoChannel::AddScreencast(
+    uint32 ssrc, const ScreencastId& id) {
+  AddScreencastMessageData data(ssrc, id);
+  Send(MSG_ADDSCREENCAST, &data);
+  return data.result;
+}
+
+bool VideoChannel::SetCapturer(uint32 ssrc, VideoCapturer* capturer) {
+  SetCapturerMessageData data(ssrc, capturer);
+  Send(MSG_SETCAPTURER, &data);
+  return data.result;
+}
+
+bool VideoChannel::RemoveScreencast(uint32 ssrc) {
+  RemoveScreencastMessageData data(ssrc);
+  Send(MSG_REMOVESCREENCAST, &data);
+  return data.result;
+}
+
+bool VideoChannel::IsScreencasting() {
+  IsScreencastingMessageData data;
+  Send(MSG_ISSCREENCASTING, &data);
+  return data.result;
+}
+
+int VideoChannel::ScreencastFps(uint32 ssrc) {
+  ScreencastFpsMessageData data(ssrc);
+  Send(MSG_SCREENCASTFPS, &data);
+  return data.result;
+}
+
+bool VideoChannel::SendIntraFrame() {
+  Send(MSG_SENDINTRAFRAME);
+  return true;
+}
+
+bool VideoChannel::RequestIntraFrame() {
+  Send(MSG_REQUESTINTRAFRAME);
+  return true;
+}
+
+void VideoChannel::SetScreenCaptureFactory(
+    ScreenCapturerFactory* screencapture_factory) {
+  SetScreenCaptureFactoryMessageData data(screencapture_factory);
+  Send(MSG_SETSCREENCASTFACTORY, &data);
+}
+
+void VideoChannel::ChangeState() {
+  // Render incoming data if we're the active call, and we have the local
+  // content. We receive data on the default channel and multiplexed streams.
+  bool recv = IsReadyToReceive();
+  if (!media_channel()->SetRender(recv)) {
+    LOG(LS_ERROR) << "Failed to SetRender on video channel";
+    // TODO(gangji): Report error back to server.
+  }
+
+  // Send outgoing data if we're the active call, we have the remote content,
+  // and we have had some form of connectivity.
+  bool send = IsReadyToSend();
+  if (!media_channel()->SetSend(send)) {
+    LOG(LS_ERROR) << "Failed to SetSend on video channel";
+    // TODO(gangji): Report error back to server.
+  }
+
+  LOG(LS_INFO) << "Changing video state, recv=" << recv << " send=" << send;
+}
+
+bool VideoChannel::GetStats(VideoMediaInfo* stats) {
+  VideoStatsMessageData data(stats);
+  Send(MSG_GETSTATS, &data);
+  return data.result;
+}
+
+void VideoChannel::StartMediaMonitor(int cms) {
+  media_monitor_.reset(new VideoMediaMonitor(media_channel(), worker_thread(),
+      talk_base::Thread::Current()));
+  media_monitor_->SignalUpdate.connect(
+      this, &VideoChannel::OnMediaMonitorUpdate);
+  media_monitor_->Start(cms);
+}
+
+void VideoChannel::StopMediaMonitor() {
+  if (media_monitor_) {
+    media_monitor_->Stop();
+    media_monitor_.reset();
+  }
+}
+
+const ContentInfo* VideoChannel::GetFirstContent(
+    const SessionDescription* sdesc) {
+  return GetFirstVideoContent(sdesc);
+}
+
+bool VideoChannel::SetLocalContent_w(const MediaContentDescription* content,
+                                     ContentAction action) {
+  ASSERT(worker_thread() == talk_base::Thread::Current());
+  LOG(LS_INFO) << "Setting local video description";
+
+  const VideoContentDescription* video =
+      static_cast<const VideoContentDescription*>(content);
+  ASSERT(video != NULL);
+  if (!video) return false;
+
+  bool ret = SetBaseLocalContent_w(content, action);
+  // Set local video codecs (what we want to receive).
+  if (action != CA_UPDATE || video->has_codecs()) {
+    ret &= media_channel()->SetRecvCodecs(video->codecs());
+  }
+
+  if (action != CA_UPDATE) {
+    VideoOptions video_options;
+    media_channel()->GetOptions(&video_options);
+    video_options.buffered_mode_latency.Set(video->buffered_mode_latency());
+
+    if (!media_channel()->SetOptions(video_options)) {
+      // Log an error on failure, but don't abort the call.
+      LOG(LS_ERROR) << "Failed to set video channel options";
+    }
+  }
+
+  // If everything worked, see if we can start receiving.
+  if (ret) {
+    ChangeState();
+  } else {
+    LOG(LS_WARNING) << "Failed to set local video description";
+  }
+  return ret;
+}
+
+bool VideoChannel::SetRemoteContent_w(const MediaContentDescription* content,
+                                      ContentAction action) {
+  ASSERT(worker_thread() == talk_base::Thread::Current());
+  LOG(LS_INFO) << "Setting remote video description";
+
+  const VideoContentDescription* video =
+      static_cast<const VideoContentDescription*>(content);
+  ASSERT(video != NULL);
+  if (!video) return false;
+
+  bool ret = true;
+  // Set remote video codecs (what the other side wants to receive).
+  if (action != CA_UPDATE || video->has_codecs()) {
+    ret &= media_channel()->SetSendCodecs(video->codecs());
+  }
+
+  ret &= SetBaseRemoteContent_w(content, action);
+
+  if (action != CA_UPDATE) {
+    // Tweak our video processing settings, if needed.
+    VideoOptions video_options;
+    media_channel()->GetOptions(&video_options);
+    video_options.conference_mode.Set(video->conference_mode());
+    video_options.buffered_mode_latency.Set(video->buffered_mode_latency());
+
+    if (!media_channel()->SetOptions(video_options)) {
+      // Log an error on failure, but don't abort the call.
+      LOG(LS_ERROR) << "Failed to set video channel options";
+    }
+  }
+
+  // If everything worked, see if we can start sending.
+  if (ret) {
+    ChangeState();
+  } else {
+    LOG(LS_WARNING) << "Failed to set remote video description";
+  }
+  return ret;
+}
+
+bool VideoChannel::ApplyViewRequest_w(const ViewRequest& request) {
+  bool ret = true;
+  // Set the send format for each of the local streams. If the view request
+  // does not contain a local stream, set its send format to 0x0, which will
+  // drop all frames.
+  for (std::vector<StreamParams>::const_iterator it = local_streams().begin();
+      it != local_streams().end(); ++it) {
+    VideoFormat format(0, 0, 0, cricket::FOURCC_I420);
+    StaticVideoViews::const_iterator view;
+    for (view = request.static_video_views.begin();
+         view != request.static_video_views.end(); ++view) {
+      if (view->selector.Matches(*it)) {
+        format.width = view->width;
+        format.height = view->height;
+        format.interval = cricket::VideoFormat::FpsToInterval(view->framerate);
+        break;
+      }
+    }
+
+    ret &= media_channel()->SetSendStreamFormat(it->first_ssrc(), format);
+  }
+
+  // Check if the view request has invalid streams.
+  for (StaticVideoViews::const_iterator it = request.static_video_views.begin();
+      it != request.static_video_views.end(); ++it) {
+    if (!GetStream(local_streams(), it->selector, NULL)) {
+      LOG(LS_WARNING) << "View request for ("
+                      << it->selector.ssrc << ", '"
+                      << it->selector.groupid << "', '"
+                      << it->selector.streamid << "'"
+                      << ") is not in the local streams.";
+    }
+  }
+
+  return ret;
+}
+
+void VideoChannel::SetRenderer_w(uint32 ssrc, VideoRenderer* renderer) {
+  media_channel()->SetRenderer(ssrc, renderer);
+}
+
+VideoCapturer* VideoChannel::AddScreencast_w(
+    uint32 ssrc, const ScreencastId& id) {
+  if (screencast_capturers_.find(ssrc) != screencast_capturers_.end()) {
+    return NULL;
+  }
+  VideoCapturer* screen_capturer =
+      screencapture_factory_->CreateScreenCapturer(id);
+  if (!screen_capturer) {
+    return NULL;
+  }
+  screen_capturer->SignalStateChange.connect(this,
+                                             &VideoChannel::OnStateChange);
+  screencast_capturers_[ssrc] = screen_capturer;
+  return screen_capturer;
+}
+
+bool VideoChannel::SetCapturer_w(uint32 ssrc, VideoCapturer* capturer) {
+  return media_channel()->SetCapturer(ssrc, capturer);
+}
+
+bool VideoChannel::RemoveScreencast_w(uint32 ssrc) {
+  ScreencastMap::iterator iter = screencast_capturers_.find(ssrc);
+  if (iter  == screencast_capturers_.end()) {
+    return false;
+  }
+  // Clean up VideoCapturer.
+  delete iter->second;
+  screencast_capturers_.erase(iter);
+  return true;
+}
+
+bool VideoChannel::IsScreencasting_w() const {
+  return !screencast_capturers_.empty();
+}
+
+int VideoChannel::ScreencastFps_w(uint32 ssrc) const {
+  ScreencastMap::const_iterator iter = screencast_capturers_.find(ssrc);
+  if (iter == screencast_capturers_.end()) {
+    return 0;
+  }
+  VideoCapturer* capturer = iter->second;
+  const VideoFormat* video_format = capturer->GetCaptureFormat();
+  return VideoFormat::IntervalToFps(video_format->interval);
+}
+
+void VideoChannel::SetScreenCaptureFactory_w(
+    ScreenCapturerFactory* screencapture_factory) {
+  if (screencapture_factory == NULL) {
+    screencapture_factory_.reset(CreateScreenCapturerFactory());
+  } else {
+    screencapture_factory_.reset(screencapture_factory);
+  }
+}
+
+bool VideoChannel::GetStats_w(VideoMediaInfo* stats) {
+  return media_channel()->GetStats(stats);
+}
+
+void VideoChannel::OnScreencastWindowEvent_s(uint32 ssrc,
+                                             talk_base::WindowEvent we) {
+  ASSERT(signaling_thread() == talk_base::Thread::Current());
+  SignalScreencastWindowEvent(ssrc, we);
+}
+
+bool VideoChannel::SetChannelOptions(const VideoOptions &options) {
+  VideoOptionsMessageData data(options);
+  Send(MSG_SETCHANNELOPTIONS, &data);
+  return data.result;
+}
+
+bool VideoChannel::SetChannelOptions_w(const VideoOptions &options) {
+  return media_channel()->SetOptions(options);
+}
+
+void VideoChannel::OnMessage(talk_base::Message *pmsg) {
+  switch (pmsg->message_id) {
+    case MSG_SETRENDERER: {
+      const VideoRenderMessageData* data =
+          static_cast<VideoRenderMessageData*>(pmsg->pdata);
+      SetRenderer_w(data->ssrc, data->renderer);
+      break;
+    }
+    case MSG_ADDSCREENCAST: {
+      AddScreencastMessageData* data =
+          static_cast<AddScreencastMessageData*>(pmsg->pdata);
+      data->result = AddScreencast_w(data->ssrc, data->window_id);
+      break;
+    }
+    case MSG_SETCAPTURER: {
+      SetCapturerMessageData* data =
+          static_cast<SetCapturerMessageData*>(pmsg->pdata);
+      data->result = SetCapturer_w(data->ssrc, data->capturer);
+      break;
+    }
+    case MSG_REMOVESCREENCAST: {
+      RemoveScreencastMessageData* data =
+          static_cast<RemoveScreencastMessageData*>(pmsg->pdata);
+      data->result = RemoveScreencast_w(data->ssrc);
+      break;
+    }
+    case MSG_SCREENCASTWINDOWEVENT: {
+      const ScreencastEventMessageData* data =
+          static_cast<ScreencastEventMessageData*>(pmsg->pdata);
+      OnScreencastWindowEvent_s(data->ssrc, data->event);
+      delete data;
+      break;
+    }
+    case  MSG_ISSCREENCASTING: {
+      IsScreencastingMessageData* data =
+          static_cast<IsScreencastingMessageData*>(pmsg->pdata);
+      data->result = IsScreencasting_w();
+      break;
+    }
+    case MSG_SCREENCASTFPS: {
+      ScreencastFpsMessageData* data =
+          static_cast<ScreencastFpsMessageData*>(pmsg->pdata);
+      data->result = ScreencastFps_w(data->ssrc);
+      break;
+    }
+    case MSG_SENDINTRAFRAME: {
+      SendIntraFrame_w();
+      break;
+    }
+    case MSG_REQUESTINTRAFRAME: {
+      RequestIntraFrame_w();
+      break;
+    }
+    case MSG_SETCHANNELOPTIONS: {
+      VideoOptionsMessageData* data =
+         static_cast<VideoOptionsMessageData*>(pmsg->pdata);
+      data->result = SetChannelOptions_w(data->options);
+      break;
+    }
+    case MSG_CHANNEL_ERROR: {
+      const VideoChannelErrorMessageData* data =
+          static_cast<VideoChannelErrorMessageData*>(pmsg->pdata);
+      SignalMediaError(this, data->ssrc, data->error);
+      delete data;
+      break;
+    }
+    case MSG_HANDLEVIEWREQUEST: {
+      ViewRequestMessageData* data =
+          static_cast<ViewRequestMessageData*>(pmsg->pdata);
+      data->result = ApplyViewRequest_w(data->request);
+      break;
+    }
+    case MSG_SETSCREENCASTFACTORY: {
+      SetScreenCaptureFactoryMessageData* data =
+          static_cast<SetScreenCaptureFactoryMessageData*>(pmsg->pdata);
+      SetScreenCaptureFactory_w(data->screencapture_factory);
+    }
+    case MSG_GETSTATS: {
+      VideoStatsMessageData* data =
+          static_cast<VideoStatsMessageData*>(pmsg->pdata);
+      data->result = GetStats_w(data->stats);
+      break;
+    }
+    default:
+      BaseChannel::OnMessage(pmsg);
+      break;
+  }
+}
+
+void VideoChannel::OnConnectionMonitorUpdate(
+    SocketMonitor *monitor, const std::vector<ConnectionInfo> &infos) {
+  SignalConnectionMonitor(this, infos);
+}
+
+// TODO(pthatcher): Look into removing duplicate code between
+// audio, video, and data, perhaps by using templates.
+void VideoChannel::OnMediaMonitorUpdate(
+    VideoMediaChannel* media_channel, const VideoMediaInfo &info) {
+  ASSERT(media_channel == this->media_channel());
+  SignalMediaMonitor(this, info);
+}
+
+void VideoChannel::OnScreencastWindowEvent(uint32 ssrc,
+                                           talk_base::WindowEvent event) {
+  ScreencastEventMessageData* pdata =
+      new ScreencastEventMessageData(ssrc, event);
+  signaling_thread()->Post(this, MSG_SCREENCASTWINDOWEVENT, pdata);
+}
+
+void VideoChannel::OnStateChange(VideoCapturer* capturer, CaptureState ev) {
+  // Map capturer events to window events. In the future we may want to simply
+  // pass these events up directly.
+  talk_base::WindowEvent we;
+  if (ev == CS_STOPPED) {
+    we = talk_base::WE_CLOSE;
+  } else if (ev == CS_PAUSED) {
+    we = talk_base::WE_MINIMIZE;
+  } else if (ev == CS_RUNNING && previous_we_ == talk_base::WE_MINIMIZE) {
+    we = talk_base::WE_RESTORE;
+  } else {
+    return;
+  }
+  previous_we_ = we;
+
+  uint32 ssrc = 0;
+  if (!GetLocalSsrc(capturer, &ssrc)) {
+    return;
+  }
+  ScreencastEventMessageData* pdata =
+      new ScreencastEventMessageData(ssrc, we);
+  signaling_thread()->Post(this, MSG_SCREENCASTWINDOWEVENT, pdata);
+}
+
+bool VideoChannel::GetLocalSsrc(const VideoCapturer* capturer, uint32* ssrc) {
+  *ssrc = 0;
+  for (ScreencastMap::iterator iter = screencast_capturers_.begin();
+       iter != screencast_capturers_.end(); ++iter) {
+    if (iter->second == capturer) {
+      *ssrc = iter->first;
+      return true;
+    }
+  }
+  return false;
+}
+
+void VideoChannel::OnVideoChannelError(uint32 ssrc,
+                                       VideoMediaChannel::Error error) {
+  VideoChannelErrorMessageData* data = new VideoChannelErrorMessageData(
+      ssrc, error);
+  signaling_thread()->Post(this, MSG_CHANNEL_ERROR, data);
+}
+
+void VideoChannel::OnSrtpError(uint32 ssrc, SrtpFilter::Mode mode,
+                               SrtpFilter::Error error) {
+  switch (error) {
+    case SrtpFilter::ERROR_FAIL:
+      OnVideoChannelError(ssrc, (mode == SrtpFilter::PROTECT) ?
+                          VideoMediaChannel::ERROR_REC_SRTP_ERROR :
+                          VideoMediaChannel::ERROR_PLAY_SRTP_ERROR);
+      break;
+    case SrtpFilter::ERROR_AUTH:
+      OnVideoChannelError(ssrc, (mode == SrtpFilter::PROTECT) ?
+                          VideoMediaChannel::ERROR_REC_SRTP_AUTH_FAILED :
+                          VideoMediaChannel::ERROR_PLAY_SRTP_AUTH_FAILED);
+      break;
+    case SrtpFilter::ERROR_REPLAY:
+      // Only receving channel should have this error.
+      ASSERT(mode == SrtpFilter::UNPROTECT);
+      // TODO(gangji): Turn on the signaling of replay error once we have
+      // switched to the new mechanism for doing video retransmissions.
+      // OnVideoChannelError(ssrc, VideoMediaChannel::ERROR_PLAY_SRTP_REPLAY);
+      break;
+    default:
+      break;
+  }
+}
+
+
+void VideoChannel::GetSrtpCiphers(std::vector<std::string>* ciphers) const {
+  GetSupportedVideoCryptoSuites(ciphers);
+}
+
+DataChannel::DataChannel(talk_base::Thread* thread,
+                         DataMediaChannel* media_channel,
+                         BaseSession* session,
+                         const std::string& content_name,
+                         bool rtcp)
+    // MediaEngine is NULL
+    : BaseChannel(thread, NULL, media_channel, session, content_name, rtcp),
+      data_channel_type_(cricket::DCT_NONE) {
+}
+
+DataChannel::~DataChannel() {
+  StopMediaMonitor();
+  // this can't be done in the base class, since it calls a virtual
+  DisableMedia_w();
+}
+
+bool DataChannel::Init() {
+  TransportChannel* rtcp_channel = rtcp() ? session()->CreateChannel(
+      content_name(), "data_rtcp", ICE_CANDIDATE_COMPONENT_RTCP) : NULL;
+  if (!BaseChannel::Init(session()->CreateChannel(
+          content_name(), "data_rtp", ICE_CANDIDATE_COMPONENT_RTP),
+          rtcp_channel)) {
+    return false;
+  }
+  media_channel()->SignalDataReceived.connect(
+      this, &DataChannel::OnDataReceived);
+  media_channel()->SignalMediaError.connect(
+      this, &DataChannel::OnDataChannelError);
+  srtp_filter()->SignalSrtpError.connect(
+      this, &DataChannel::OnSrtpError);
+  return true;
+}
+
+bool DataChannel::SendData(const SendDataParams& params,
+                           const talk_base::Buffer& payload,
+                           SendDataResult* result) {
+  SendDataMessageData message_data(params, &payload, result);
+  Send(MSG_SENDDATA, &message_data);
+  return message_data.succeeded;
+}
+
+const ContentInfo* DataChannel::GetFirstContent(
+    const SessionDescription* sdesc) {
+  return GetFirstDataContent(sdesc);
+}
+
+
+static bool IsRtpPacket(const talk_base::Buffer* packet) {
+  int version;
+  if (!GetRtpVersion(packet->data(), packet->length(), &version)) {
+    return false;
+  }
+
+  return version == 2;
+}
+
+bool DataChannel::WantsPacket(bool rtcp, talk_base::Buffer* packet) {
+  if (data_channel_type_ == DCT_SCTP) {
+    // TODO(pthatcher): Do this in a more robust way by checking for
+    // SCTP or DTLS.
+    return !IsRtpPacket(packet);
+  } else if (data_channel_type_ == DCT_RTP) {
+    return BaseChannel::WantsPacket(rtcp, packet);
+  }
+  return false;
+}
+
+// Sets the maximum bandwidth.  Anything over this will be dropped.
+bool DataChannel::SetMaxSendBandwidth_w(int max_bps) {
+  LOG(LS_INFO) << "DataChannel: Setting max bandwidth to " << max_bps;
+  return media_channel()->SetSendBandwidth(false, max_bps);
+}
+
+bool DataChannel::SetDataChannelType(DataChannelType new_data_channel_type) {
+  // It hasn't been set before, so set it now.
+  if (data_channel_type_ == DCT_NONE) {
+    data_channel_type_ = new_data_channel_type;
+    return true;
+  }
+
+  // It's been set before, but doesn't match.  That's bad.
+  if (data_channel_type_ != new_data_channel_type) {
+    LOG(LS_WARNING) << "Data channel type mismatch."
+                    << " Expected " << data_channel_type_
+                    << " Got " << new_data_channel_type;
+    return false;
+  }
+
+  // It's hasn't changed.  Nothing to do.
+  return true;
+}
+
+bool DataChannel::SetDataChannelTypeFromContent(
+    const DataContentDescription* content) {
+  bool is_sctp = ((content->protocol() == kMediaProtocolSctp) ||
+                  (content->protocol() == kMediaProtocolDtlsSctp));
+  DataChannelType data_channel_type = is_sctp ? DCT_SCTP : DCT_RTP;
+  return SetDataChannelType(data_channel_type);
+}
+
+bool DataChannel::SetLocalContent_w(const MediaContentDescription* content,
+                                    ContentAction action) {
+  ASSERT(worker_thread() == talk_base::Thread::Current());
+  LOG(LS_INFO) << "Setting local data description";
+
+  const DataContentDescription* data =
+      static_cast<const DataContentDescription*>(content);
+  ASSERT(data != NULL);
+  if (!data) return false;
+
+  bool ret = false;
+  if (!SetDataChannelTypeFromContent(data)) {
+    return false;
+  }
+
+  if (data_channel_type_ == DCT_SCTP) {
+    // SCTP data channels don't need the rest of the stuff.
+    ret = UpdateLocalStreams_w(data->streams(), action);
+    if (ret) {
+      set_local_content_direction(content->direction());
+    }
+  } else {
+    ret = SetBaseLocalContent_w(content, action);
+
+    if (action != CA_UPDATE || data->has_codecs()) {
+      ret &= media_channel()->SetRecvCodecs(data->codecs());
+    }
+  }
+
+  // If everything worked, see if we can start receiving.
+  if (ret) {
+    ChangeState();
+  } else {
+    LOG(LS_WARNING) << "Failed to set local data description";
+  }
+  return ret;
+}
+
+bool DataChannel::SetRemoteContent_w(const MediaContentDescription* content,
+                                     ContentAction action) {
+  ASSERT(worker_thread() == talk_base::Thread::Current());
+
+  const DataContentDescription* data =
+      static_cast<const DataContentDescription*>(content);
+  ASSERT(data != NULL);
+  if (!data) return false;
+
+  bool ret = true;
+  if (!SetDataChannelTypeFromContent(data)) {
+    return false;
+  }
+
+  if (data_channel_type_ == DCT_SCTP) {
+    LOG(LS_INFO) << "Setting SCTP remote data description";
+    // SCTP data channels don't need the rest of the stuff.
+    ret = UpdateRemoteStreams_w(content->streams(), action);
+    if (ret) {
+      set_remote_content_direction(content->direction());
+    }
+  } else {
+    // If the remote data doesn't have codecs and isn't an update, it
+    // must be empty, so ignore it.
+    if (action != CA_UPDATE && !data->has_codecs()) {
+      return true;
+    }
+    LOG(LS_INFO) << "Setting remote data description";
+
+    // Set remote video codecs (what the other side wants to receive).
+    if (action != CA_UPDATE || data->has_codecs()) {
+      ret &= media_channel()->SetSendCodecs(data->codecs());
+    }
+
+    if (ret) {
+      ret &= SetBaseRemoteContent_w(content, action);
+    }
+
+    if (action != CA_UPDATE) {
+      int bandwidth_bps = data->bandwidth();
+      bool auto_bandwidth = (bandwidth_bps == kAutoBandwidth);
+      ret &= media_channel()->SetSendBandwidth(auto_bandwidth, bandwidth_bps);
+    }
+  }
+
+  // If everything worked, see if we can start sending.
+  if (ret) {
+    ChangeState();
+  } else {
+    LOG(LS_WARNING) << "Failed to set remote data description";
+  }
+  return ret;
+}
+
+void DataChannel::ChangeState() {
+  // Render incoming data if we're the active call, and we have the local
+  // content. We receive data on the default channel and multiplexed streams.
+  bool recv = IsReadyToReceive();
+  if (!media_channel()->SetReceive(recv)) {
+    LOG(LS_ERROR) << "Failed to SetReceive on data channel";
+  }
+
+  // Send outgoing data if we're the active call, we have the remote content,
+  // and we have had some form of connectivity.
+  bool send = IsReadyToSend();
+  if (!media_channel()->SetSend(send)) {
+    LOG(LS_ERROR) << "Failed to SetSend on data channel";
+  }
+
+  // Post to trigger SignalReadyToSendData.
+  signaling_thread()->Post(this, MSG_READYTOSENDDATA,
+                           new BoolMessageData(send));
+
+  LOG(LS_INFO) << "Changing data state, recv=" << recv << " send=" << send;
+}
+
+void DataChannel::OnMessage(talk_base::Message *pmsg) {
+  switch (pmsg->message_id) {
+    case MSG_READYTOSENDDATA: {
+      BoolMessageData* data = static_cast<BoolMessageData*>(pmsg->pdata);
+      SignalReadyToSendData(data->data());
+      delete data;
+      break;
+    }
+    case MSG_SENDDATA: {
+      SendDataMessageData* msg =
+          static_cast<SendDataMessageData*>(pmsg->pdata);
+      msg->succeeded = media_channel()->SendData(
+          msg->params, *(msg->payload), msg->result);
+      break;
+    }
+    case MSG_DATARECEIVED: {
+      DataReceivedMessageData* data =
+          static_cast<DataReceivedMessageData*>(pmsg->pdata);
+      SignalDataReceived(this, data->params, data->payload);
+      delete data;
+      break;
+    }
+    case MSG_CHANNEL_ERROR: {
+      const DataChannelErrorMessageData* data =
+          static_cast<DataChannelErrorMessageData*>(pmsg->pdata);
+      SignalMediaError(this, data->ssrc, data->error);
+      delete data;
+      break;
+    }
+    default:
+      BaseChannel::OnMessage(pmsg);
+      break;
+  }
+}
+
+void DataChannel::OnConnectionMonitorUpdate(
+    SocketMonitor* monitor, const std::vector<ConnectionInfo>& infos) {
+  SignalConnectionMonitor(this, infos);
+}
+
+void DataChannel::StartMediaMonitor(int cms) {
+  media_monitor_.reset(new DataMediaMonitor(media_channel(), worker_thread(),
+      talk_base::Thread::Current()));
+  media_monitor_->SignalUpdate.connect(
+      this, &DataChannel::OnMediaMonitorUpdate);
+  media_monitor_->Start(cms);
+}
+
+void DataChannel::StopMediaMonitor() {
+  if (media_monitor_) {
+    media_monitor_->Stop();
+    media_monitor_->SignalUpdate.disconnect(this);
+    media_monitor_.reset();
+  }
+}
+
+void DataChannel::OnMediaMonitorUpdate(
+    DataMediaChannel* media_channel, const DataMediaInfo& info) {
+  ASSERT(media_channel == this->media_channel());
+  SignalMediaMonitor(this, info);
+}
+
+void DataChannel::OnDataReceived(
+    const ReceiveDataParams& params, const char* data, size_t len) {
+  DataReceivedMessageData* msg = new DataReceivedMessageData(
+      params, data, len);
+  signaling_thread()->Post(this, MSG_DATARECEIVED, msg);
+}
+
+void DataChannel::OnDataChannelError(
+    uint32 ssrc, DataMediaChannel::Error err) {
+  DataChannelErrorMessageData* data = new DataChannelErrorMessageData(
+      ssrc, err);
+  signaling_thread()->Post(this, MSG_CHANNEL_ERROR, data);
+}
+
+void DataChannel::OnSrtpError(uint32 ssrc, SrtpFilter::Mode mode,
+                              SrtpFilter::Error error) {
+  switch (error) {
+    case SrtpFilter::ERROR_FAIL:
+      OnDataChannelError(ssrc, (mode == SrtpFilter::PROTECT) ?
+                         DataMediaChannel::ERROR_SEND_SRTP_ERROR :
+                         DataMediaChannel::ERROR_RECV_SRTP_ERROR);
+      break;
+    case SrtpFilter::ERROR_AUTH:
+      OnDataChannelError(ssrc, (mode == SrtpFilter::PROTECT) ?
+                         DataMediaChannel::ERROR_SEND_SRTP_AUTH_FAILED :
+                         DataMediaChannel::ERROR_RECV_SRTP_AUTH_FAILED);
+      break;
+    case SrtpFilter::ERROR_REPLAY:
+      // Only receving channel should have this error.
+      ASSERT(mode == SrtpFilter::UNPROTECT);
+      OnDataChannelError(ssrc, DataMediaChannel::ERROR_RECV_SRTP_REPLAY);
+      break;
+    default:
+      break;
+  }
+}
+
+void DataChannel::GetSrtpCiphers(std::vector<std::string>* ciphers) const {
+  GetSupportedDataCryptoSuites(ciphers);
+}
+
+bool DataChannel::ShouldSetupDtlsSrtp() const {
+  return (data_channel_type_ == DCT_RTP);
+}
+
+}  // namespace cricket