TransportController refactoring.

webrtc/p2p/base/session.cc

Index: webrtc/p2p/base/session.cc
diff --git a/webrtc/p2p/base/session.cc b/webrtc/p2p/base/session.cc
index 23680b9be83b858ab7c8a19127e73e4510adfb6b..83edb63ea588d64590eca6dfb8ffc8b22f04873b 100644
--- a/webrtc/p2p/base/session.cc
+++ b/webrtc/p2p/base/session.cc
@@ -10,11 +10,6 @@
 
 #include "webrtc/p2p/base/session.h"
 
-#include "webrtc/p2p/base/dtlstransport.h"
-#include "webrtc/p2p/base/p2ptransport.h"
-#include "webrtc/p2p/base/transport.h"
-#include "webrtc/p2p/base/transportchannelproxy.h"
-#include "webrtc/p2p/base/transportinfo.h"
 #include "webrtc/base/bind.h"
 #include "webrtc/base/common.h"
 #include "webrtc/base/helpers.h"
@@ -22,266 +17,15 @@
 #include "webrtc/base/scoped_ptr.h"
 #include "webrtc/base/stringencode.h"
 #include "webrtc/base/sslstreamadapter.h"
-
+#include "webrtc/p2p/base/transport.h"
+#include "webrtc/p2p/base/transportinfo.h"
+#include "webrtc/p2p/base/transportcontroller.h"
 #include "webrtc/p2p/base/constants.h"
 
 namespace cricket {
 
 using rtc::Bind;
 
-TransportProxy::~TransportProxy() {
-  for (ChannelMap::iterator iter = channels_.begin();
-       iter != channels_.end(); ++iter) {
-    iter->second->SignalDestroyed(iter->second);
-    delete iter->second;
-  }
-}
-
-TransportChannel* TransportProxy::GetChannel(int component) {
-  ASSERT(rtc::Thread::Current() == worker_thread_);
-  return GetChannelProxy(component);
-}
-
-TransportChannel* TransportProxy::CreateChannel(int component) {
-  ASSERT(rtc::Thread::Current() == worker_thread_);
-  ASSERT(GetChannel(component) == NULL);
-  ASSERT(!transport_->get()->HasChannel(component));
-
-  // We always create a proxy in case we need to change out the transport later.
-  TransportChannelProxy* channel_proxy =
-      new TransportChannelProxy(content_name(), component);
-  channels_[component] = channel_proxy;
-
-  // If we're already negotiated, create an impl and hook it up to the proxy
-  // channel. If we're connecting, create an impl but don't hook it up yet.
-  if (negotiated_) {
-    CreateChannelImpl_w(component);
-    SetChannelImplFromTransport_w(channel_proxy, component);
-  } else if (connecting_) {
-    CreateChannelImpl_w(component);
-  }
-  return channel_proxy;
-}
-
-bool TransportProxy::HasChannel(int component) {
-  return transport_->get()->HasChannel(component);
-}
-
-void TransportProxy::DestroyChannel(int component) {
-  ASSERT(rtc::Thread::Current() == worker_thread_);
-  TransportChannelProxy* channel_proxy = GetChannelProxy(component);
-  if (channel_proxy) {
-    // If the state of TransportProxy is not NEGOTIATED then
-    // TransportChannelProxy and its impl are not connected. Both must
-    // be connected before deletion.
-    //
-    // However, if we haven't entered the connecting state then there
-    // is no implementation to hook up.
-    if (connecting_ && !negotiated_) {
-      SetChannelImplFromTransport_w(channel_proxy, component);
-    }
-
-    channels_.erase(component);
-    channel_proxy->SignalDestroyed(channel_proxy);
-    delete channel_proxy;
-  }
-}
-
-void TransportProxy::ConnectChannels() {
-  if (!connecting_) {
-    if (!negotiated_) {
-      for (auto& iter : channels_) {
-        CreateChannelImpl(iter.first);
-      }
-    }
-    connecting_ = true;
-  }
-  // TODO(juberti): Right now Transport::ConnectChannels doesn't work if we
-  // don't have any channels yet, so we need to allow this method to be called
-  // multiple times. Once we fix Transport, we can move this call inside the
-  // if (!connecting_) block.
-  transport_->get()->ConnectChannels();
-}
-
-void TransportProxy::CompleteNegotiation() {
-  if (!negotiated_) {
-    // Negotiating assumes connecting_ has happened and
-    // implementations exist. If not we need to create the
-    // implementations.
-    for (auto& iter : channels_) {
-      if (!connecting_) {
-        CreateChannelImpl(iter.first);
-      }
-      SetChannelImplFromTransport(iter.second, iter.first);
-    }
-    negotiated_ = true;
-  }
-}
-
-void TransportProxy::AddSentCandidates(const Candidates& candidates) {
-  for (Candidates::const_iterator cand = candidates.begin();
-       cand != candidates.end(); ++cand) {
-    sent_candidates_.push_back(*cand);
-  }
-}
-
-void TransportProxy::AddUnsentCandidates(const Candidates& candidates) {
-  for (Candidates::const_iterator cand = candidates.begin();
-       cand != candidates.end(); ++cand) {
-    unsent_candidates_.push_back(*cand);
-  }
-}
-
-TransportChannelProxy* TransportProxy::GetChannelProxy(int component) const {
-  ChannelMap::const_iterator iter = channels_.find(component);
-  return (iter != channels_.end()) ? iter->second : NULL;
-}
-
-void TransportProxy::CreateChannelImpl(int component) {
-  worker_thread_->Invoke<void>(Bind(
-      &TransportProxy::CreateChannelImpl_w, this, component));
-}
-
-void TransportProxy::CreateChannelImpl_w(int component) {
-  ASSERT(rtc::Thread::Current() == worker_thread_);
-  transport_->get()->CreateChannel(component);
-}
-
-void TransportProxy::SetChannelImplFromTransport(TransportChannelProxy* proxy,
-                                                 int component) {
-  worker_thread_->Invoke<void>(Bind(
-      &TransportProxy::SetChannelImplFromTransport_w, this, proxy, component));
-}
-
-void TransportProxy::SetChannelImplFromTransport_w(TransportChannelProxy* proxy,
-                                                   int component) {
-  ASSERT(rtc::Thread::Current() == worker_thread_);
-  TransportChannelImpl* impl = transport_->get()->GetChannel(component);
-  ASSERT(impl != NULL);
-  ReplaceChannelImpl_w(proxy, impl);
-}
-
-void TransportProxy::ReplaceChannelImpl(TransportChannelProxy* proxy,
-                                        TransportChannelImpl* impl) {
-  worker_thread_->Invoke<void>(Bind(
-      &TransportProxy::ReplaceChannelImpl_w, this, proxy, impl));
-}
-
-void TransportProxy::ReplaceChannelImpl_w(TransportChannelProxy* proxy,
-                                          TransportChannelImpl* impl) {
-  ASSERT(rtc::Thread::Current() == worker_thread_);
-  ASSERT(proxy != NULL);
-  proxy->SetImplementation(impl);
-}
-
-// This function muxes |this| onto |target| by repointing |this| at
-// |target|'s transport and setting our TransportChannelProxies
-// to point to |target|'s underlying implementations.
-bool TransportProxy::SetupMux(TransportProxy* target) {
-  // Bail out if there's nothing to do.
-  if (transport_ == target->transport_) {
-    return true;
-  }
-
-  // Run through all channels and remove any non-rtp transport channels before
-  // setting target transport channels.
-  for (ChannelMap::const_iterator iter = channels_.begin();
-       iter != channels_.end(); ++iter) {
-    if (!target->transport_->get()->HasChannel(iter->first)) {
-      // Remove if channel doesn't exist in |transport_|.
-      ReplaceChannelImpl(iter->second, NULL);
-    } else {
-      // Replace the impl for all the TransportProxyChannels with the channels
-      // from |target|'s transport. Fail if there's not an exact match.
-      ReplaceChannelImpl(
-          iter->second, target->transport_->get()->CreateChannel(iter->first));
-    }
-  }
-
-  // Now replace our transport. Must happen afterwards because
-  // it deletes all impls as a side effect.
-  transport_ = target->transport_;
-  transport_->get()->SignalCandidatesReady.connect(
-      this, &TransportProxy::OnTransportCandidatesReady);
-  set_candidates_allocated(target->candidates_allocated());
-  return true;
-}
-
-void TransportProxy::SetIceRole(IceRole role) {
-  transport_->get()->SetIceRole(role);
-}
-
-bool TransportProxy::SetLocalTransportDescription(
-    const TransportDescription& description,
-    ContentAction action,
-    std::string* error_desc) {
-  // If this is an answer, finalize the negotiation.
-  if (action == CA_ANSWER) {
-    CompleteNegotiation();
-  }
-  bool result = transport_->get()->SetLocalTransportDescription(description,
-                                                                action,
-                                                                error_desc);
-  if (result)
-    local_description_set_ = true;
-  return result;
-}
-
-bool TransportProxy::SetRemoteTransportDescription(
-    const TransportDescription& description,
-    ContentAction action,
-    std::string* error_desc) {
-  // If this is an answer, finalize the negotiation.
-  if (action == CA_ANSWER) {
-    CompleteNegotiation();
-  }
-  bool result = transport_->get()->SetRemoteTransportDescription(description,
-                                                                 action,
-                                                                 error_desc);
-  if (result)
-    remote_description_set_ = true;
-  return result;
-}
-
-void TransportProxy::OnSignalingReady() {
-  // If we're starting a new allocation sequence, reset our state.
-  set_candidates_allocated(false);
-  transport_->get()->OnSignalingReady();
-}
-
-bool TransportProxy::OnRemoteCandidates(const Candidates& candidates,
-                                        std::string* error) {
-  // Ensure the transport is negotiated before handling candidates.
-  // TODO(juberti): Remove this once everybody calls SetLocalTD.
-  CompleteNegotiation();
-
-  // Ignore candidates for if the proxy content_name doesn't match the content
-  // name of the actual transport. This stops video candidates from being sent
-  // down to the audio transport when BUNDLE is enabled.
-  if (content_name_ != transport_->get()->content_name()) {
-    return true;
-  }
-
-  // Verify each candidate before passing down to transport layer.
-  for (Candidates::const_iterator cand = candidates.begin();
-       cand != candidates.end(); ++cand) {
-    if (!transport_->get()->VerifyCandidate(*cand, error))
-      return false;
-    if (!HasChannel(cand->component())) {
-      *error = "Candidate has unknown component: " + cand->ToString() +
-               " for content: " + content_name_;
-      return false;
-    }
-  }
-  transport_->get()->OnRemoteCandidates(candidates);
-  return true;
-}
-
-void TransportProxy::SetCertificate(
-    const rtc::scoped_refptr<rtc::RTCCertificate>& certificate) {
-  transport_->get()->SetCertificate(certificate);
-}
-
 std::string BaseSession::StateToString(State state) {
   switch (state) {
     case STATE_INIT:
@@ -326,7 +70,6 @@ BaseSession::BaseSession(rtc::Thread* signaling_thread,
                          rtc::Thread* worker_thread,
                          PortAllocator* port_allocator,
                          const std::string& sid,
-                         const std::string& content_type,
                          bool initiator)
     : state_(STATE_INIT),
       error_(ERROR_NONE),
@@ -334,13 +77,11 @@ BaseSession::BaseSession(rtc::Thread* signaling_thread,
       worker_thread_(worker_thread),
       port_allocator_(port_allocator),
       sid_(sid),
-      content_type_(content_type),
-      initiator_(initiator),
-      ssl_max_version_(rtc::SSL_PROTOCOL_DTLS_10),
-      ice_tiebreaker_(rtc::CreateRandomId64()),
-      role_switch_(false),
-      ice_receiving_timeout_(-1) {
+      transport_controller_(new TransportController(signaling_thread,
+                                                    worker_thread,
+                                                    port_allocator)) {
   ASSERT(signaling_thread->IsCurrent());
+  set_initiator(initiator);
 }
 
 BaseSession::~BaseSession() {
@@ -350,11 +91,6 @@ BaseSession::~BaseSession() {
   LogState(state_, STATE_DEINIT);
   state_ = STATE_DEINIT;
   SignalState(this, state_);
-
-  for (TransportMap::iterator iter = transports_.begin();
-       iter != transports_.end(); ++iter) {
-    delete iter->second;
-  }
 }
 
 const SessionDescription* BaseSession::local_description() const {
@@ -384,37 +120,23 @@ void BaseSession::set_remote_description(SessionDescription* sdesc) {
     remote_description_.reset(sdesc);
 }
 
-const SessionDescription* BaseSession::initiator_description() const {
-  // TODO(tommi): Assert on thread correctness.
-  return initiator_ ? local_description_.get() : remote_description_.get();
-}
+void BaseSession::set_initiator(bool initiator) {
+  initiator_ = initiator;
 
-bool BaseSession::SetCertificate(
-    const rtc::scoped_refptr<rtc::RTCCertificate>& certificate) {
-  if (certificate_)
-    return false;
-  if (!certificate)
-    return false;
-  certificate_ = certificate;
-  for (TransportMap::iterator iter = transports_.begin();
-       iter != transports_.end(); ++iter) {
-    iter->second->SetCertificate(certificate_);
-  }
-  return true;
+  IceRole ice_role = initiator ? ICEROLE_CONTROLLING : ICEROLE_CONTROLLED;
+  transport_controller_->SetIceRole(ice_role);
 }
 
-bool BaseSession::SetSslMaxProtocolVersion(rtc::SSLProtocolVersion version) {
-  if (state_ != STATE_INIT) {
-    return false;
-  }
-
-  ssl_max_version_ = version;
-  return true;
+const SessionDescription* BaseSession::initiator_description() const {
+  // TODO(tommi): Assert on thread correctness.
+  return initiator_ ? local_description_.get() : remote_description_.get();
 }
 
 bool BaseSession::PushdownTransportDescription(ContentSource source,
                                                ContentAction action,
                                                std::string* error_desc) {
+  ASSERT(signaling_thread()->IsCurrent());
+
   if (source == CS_LOCAL) {
     return PushdownLocalTransportDescription(local_description(),
                                              action,
@@ -428,23 +150,17 @@ bool BaseSession::PushdownTransportDescription(ContentSource source,
 bool BaseSession::PushdownLocalTransportDescription(
     const SessionDescription* sdesc,
     ContentAction action,
-    std::string* error_desc) {
-  // Update the Transports with the right information, and trigger them to
-  // start connecting.
-  for (TransportMap::iterator iter = transports_.begin();
-       iter != transports_.end(); ++iter) {
-    // If no transport info was in this session description, ret == false
-    // and we just skip this one.
-    TransportDescription tdesc;
-    bool ret = GetTransportDescription(
-        sdesc, iter->second->content_name(), &tdesc);
-    if (ret) {
-      if (!iter->second->SetLocalTransportDescription(tdesc, action,
-                                                      error_desc)) {
-        return false;
-      }
-
-      iter->second->ConnectChannels();
+    std::string* err) {
+  ASSERT(signaling_thread()->IsCurrent());
+
+  if (!sdesc) {
+    return false;
+  }
+
+  for (const TransportInfo& tinfo : sdesc->transport_infos()) {
+    if (!transport_controller_->SetLocalTransportDescription(
+            tinfo.content_name, tinfo.description, action, err)) {
+      return false;
     }
   }
 
@@ -454,132 +170,21 @@ bool BaseSession::PushdownLocalTransportDescription(
 bool BaseSession::PushdownRemoteTransportDescription(
     const SessionDescription* sdesc,
     ContentAction action,
-    std::string* error_desc) {
-  // Update the Transports with the right information.
-  for (TransportMap::iterator iter = transports_.begin();
-       iter != transports_.end(); ++iter) {
-    TransportDescription tdesc;
-
-    // If no transport info was in this session description, ret == false
-    // and we just skip this one.
-    bool ret = GetTransportDescription(
-        sdesc, iter->second->content_name(), &tdesc);
-    if (ret) {
-      if (!iter->second->SetRemoteTransportDescription(tdesc, action,
-                                                       error_desc)) {
-        return false;
-      }
-    }
-  }
-
-  return true;
-}
+    std::string* err) {
+  ASSERT(signaling_thread()->IsCurrent());
 
-void BaseSession::SetIceConnectionReceivingTimeout(int timeout_ms) {
-  ice_receiving_timeout_ = timeout_ms;
-  for (const auto& kv : transport_proxies()) {
-    Transport* transport = kv.second->impl();
-    if (transport) {
-      transport->SetChannelReceivingTimeout(timeout_ms);
-    }
+  if (!sdesc) {
+    return false;
   }
-}
-
-TransportChannel* BaseSession::CreateChannel(const std::string& content_name,
-                                             int component) {
-  // We create the proxy "on demand" here because we need to support
-  // creating channels at any time, even before we send or receive
-  // initiate messages, which is before we create the transports.
-  TransportProxy* transproxy = GetOrCreateTransportProxy(content_name);
-  return transproxy->CreateChannel(component);
-}
-
-TransportChannel* BaseSession::GetChannel(const std::string& content_name,
-                                          int component) {
-  TransportProxy* transproxy = GetTransportProxy(content_name);
-  if (transproxy == NULL)
-    return NULL;
 
-  return transproxy->GetChannel(component);
-}
-
-void BaseSession::DestroyChannel(const std::string& content_name,
-                                 int component) {
-  TransportProxy* transproxy = GetTransportProxy(content_name);
-  ASSERT(transproxy != NULL);
-  transproxy->DestroyChannel(component);
-}
-
-TransportProxy* BaseSession::GetOrCreateTransportProxy(
-    const std::string& content_name) {
-  TransportProxy* transproxy = GetTransportProxy(content_name);
-  if (transproxy)
-    return transproxy;
-
-  Transport* transport = CreateTransport(content_name);
-  transport->SetIceRole(initiator_ ? ICEROLE_CONTROLLING : ICEROLE_CONTROLLED);
-  transport->SetIceTiebreaker(ice_tiebreaker_);
-  transport->SetSslMaxProtocolVersion(ssl_max_version_);
-  // TODO: Connect all the Transport signals to TransportProxy
-  // then to the BaseSession.
-  transport->SignalConnecting.connect(
-      this, &BaseSession::OnTransportConnecting);
-  transport->SignalWritableState.connect(
-      this, &BaseSession::OnTransportWritable);
-  transport->SignalReceivingState.connect(
-      this, &BaseSession::OnTransportReceiving);
-  transport->SignalRequestSignaling.connect(
-      this, &BaseSession::OnTransportRequestSignaling);
-  transport->SignalRouteChange.connect(
-      this, &BaseSession::OnTransportRouteChange);
-  transport->SignalCandidatesAllocationDone.connect(
-      this, &BaseSession::OnTransportCandidatesAllocationDone);
-  transport->SignalRoleConflict.connect(
-      this, &BaseSession::OnRoleConflict);
-  transport->SignalCompleted.connect(
-      this, &BaseSession::OnTransportCompleted);
-  transport->SignalFailed.connect(
-      this, &BaseSession::OnTransportFailed);
-
-  transproxy = new TransportProxy(worker_thread_, sid_, content_name,
-                                  new TransportWrapper(transport));
-  transproxy->SignalCandidatesReady.connect(
-      this, &BaseSession::OnTransportProxyCandidatesReady);
-  if (certificate_)
-    transproxy->SetCertificate(certificate_);
-  transports_[content_name] = transproxy;
-
-  return transproxy;
-}
-
-Transport* BaseSession::GetTransport(const std::string& content_name) {
-  TransportProxy* transproxy = GetTransportProxy(content_name);
-  if (transproxy == NULL)
-    return NULL;
-  return transproxy->impl();
-}
-
-TransportProxy* BaseSession::GetTransportProxy(
-    const std::string& content_name) {
-  TransportMap::iterator iter = transports_.find(content_name);
-  return (iter != transports_.end()) ? iter->second : NULL;
-}
-
-void BaseSession::DestroyTransportProxy(
-    const std::string& content_name) {
-  TransportMap::iterator iter = transports_.find(content_name);
-  if (iter != transports_.end()) {
-    delete iter->second;
-    transports_.erase(content_name);
+  for (const TransportInfo& tinfo : sdesc->transport_infos()) {
+    if (!transport_controller_->SetRemoteTransportDescription(
+            tinfo.content_name, tinfo.description, action, err)) {
+      return false;
+    }
   }
-}
 
-Transport* BaseSession::CreateTransport(const std::string& content_name) {
-  Transport* transport = new DtlsTransport<P2PTransport>(
-      signaling_thread(), worker_thread(), content_name, port_allocator(),
-      certificate_);
-  transport->SetChannelReceivingTimeout(ice_receiving_timeout_);
-  return transport;
+  return true;
 }
 
 void BaseSession::SetState(State state) {
@@ -601,180 +206,18 @@ void BaseSession::SetError(Error error, const std::string& error_desc) {
   }
 }
 
-void BaseSession::OnSignalingReady() {
-  ASSERT(signaling_thread()->IsCurrent());
-  for (TransportMap::iterator iter = transports_.begin();
-       iter != transports_.end(); ++iter) {
-    iter->second->OnSignalingReady();
-  }
-}
-
-// TODO(juberti): Since PushdownLocalTD now triggers the connection process to
-// start, remove this method once everyone calls PushdownLocalTD.
-void BaseSession::SpeculativelyConnectAllTransportChannels() {
-  // Put all transports into the connecting state.
-  for (TransportMap::iterator iter = transports_.begin();
-       iter != transports_.end(); ++iter) {
-    iter->second->ConnectChannels();
-  }
-}
-
-bool BaseSession::OnRemoteCandidates(const std::string& content_name,
-                                     const Candidates& candidates,
-                                     std::string* error) {
-  // Give candidates to the appropriate transport, and tell that transport
-  // to start connecting, if it's not already doing so.
-  TransportProxy* transproxy = GetTransportProxy(content_name);
-  if (!transproxy) {
-    *error = "Unknown content name " + content_name;
-    return false;
-  }
-  if (!transproxy->OnRemoteCandidates(candidates, error)) {
-    return false;
-  }
-  // TODO(juberti): Remove this call once we can be sure that we always have
-  // a local transport description (which will trigger the connection).
-  transproxy->ConnectChannels();
-  return true;
-}
-
-bool BaseSession::MaybeEnableMuxingSupport() {
-  // We need both a local and remote description to decide if we should mux.
-  if ((state_ == STATE_SENTINITIATE ||
-      state_ == STATE_RECEIVEDINITIATE) &&
-      ((local_description_ == NULL) ||
-      (remote_description_ == NULL))) {
-    return false;
-  }
-
-  // In order to perform the multiplexing, we need all proxies to be in the
-  // negotiated state, i.e. to have implementations underneath.
-  // Ensure that this is the case, regardless of whether we are going to mux.
-  for (TransportMap::iterator iter = transports_.begin();
-       iter != transports_.end(); ++iter) {
-    ASSERT(iter->second->negotiated());
-    if (!iter->second->negotiated()) {
-      return false;
-    }
-  }
-
-  // If both sides agree to BUNDLE, mux all the specified contents onto the
-  // transport belonging to the first content name in the BUNDLE group.
-  // If the contents are already muxed, this will be a no-op.
-  // TODO(juberti): Should this check that local and remote have configured
-  // BUNDLE the same way?
-  bool candidates_allocated = IsCandidateAllocationDone();
-  const ContentGroup* local_bundle_group =
-      local_description_->GetGroupByName(GROUP_TYPE_BUNDLE);
-  const ContentGroup* remote_bundle_group =
-      remote_description_->GetGroupByName(GROUP_TYPE_BUNDLE);
-  if (local_bundle_group && remote_bundle_group) {
-    if (!BundleContentGroup(local_bundle_group)) {
-      LOG(LS_WARNING) << "Failed to set up BUNDLE";
-      return false;
-    }
-
-    // If we weren't done gathering before, we might be done now, as a result
-    // of enabling mux.
-    if (!candidates_allocated) {
-      MaybeCandidateAllocationDone();
-    }
-  } else {
-    LOG(LS_INFO) << "BUNDLE group missing from remote or local description.";
-  }
-  return true;
-}
-
-bool BaseSession::BundleContentGroup(const ContentGroup* bundle_group) {
-  const std::string* content_name = bundle_group->FirstContentName();
-  if (!content_name) {
-    LOG(LS_INFO) << "No content names specified in BUNDLE group.";
-    return true;
-  }
-
-  TransportProxy* selected_proxy = GetTransportProxy(*content_name);
-  if (!selected_proxy) {
-    LOG(LS_WARNING) << "No transport found for content \""
-                    << *content_name << "\".";
-    return false;
-  }
-
-  for (TransportMap::iterator iter = transports_.begin();
-       iter != transports_.end(); ++iter) {
-    // If content is part of the mux group, then repoint its proxy at the
-    // transport object that we have chosen to mux onto. If the proxy
-    // is already pointing at the right object, it will be a no-op.
-    if (bundle_group->HasContentName(iter->first) &&
-        !iter->second->SetupMux(selected_proxy)) {
-      LOG(LS_WARNING) << "Failed to bundle " << iter->first << " to "
-                      << *content_name;
-      return false;
-    }
-    LOG(LS_INFO) << "Bundling " << iter->first << " to " << *content_name;
-  }
-
-  return true;
-}
-
-void BaseSession::OnTransportCandidatesAllocationDone(Transport* transport) {
-  // TODO(juberti): This is a clunky way of processing the done signal. Instead,
-  // TransportProxy should receive the done signal directly, set its allocated
-  // flag internally, and then reissue the done signal to Session.
-  // Overall we should make TransportProxy receive *all* the signals from
-  // Transport, since this removes the need to manually iterate over all
-  // the transports, as is needed to make sure signals are handled properly
-  // when BUNDLEing.
-  // TODO(juberti): Per b/7998978, devs and QA are hitting this assert in ways
-  // that make it prohibitively difficult to run dbg builds. Disabled for now.
-  //ASSERT(!IsCandidateAllocationDone());
-  for (TransportMap::iterator iter = transports_.begin();
-       iter != transports_.end(); ++iter) {
-    if (iter->second->impl() == transport) {
-      iter->second->set_candidates_allocated(true);
-    }
-  }
-  MaybeCandidateAllocationDone();
-}
-
-bool BaseSession::IsCandidateAllocationDone() const {
-  for (TransportMap::const_iterator iter = transports_.begin();
-       iter != transports_.end(); ++iter) {
-    if (!iter->second->candidates_allocated()) {
-      LOG(LS_INFO) << "Candidate allocation not done for "
-                   << iter->second->content_name();
-      return false;
-    }
-  }
-  return true;
-}
-
-void BaseSession::MaybeCandidateAllocationDone() {
-  if (IsCandidateAllocationDone()) {
-    LOG(LS_INFO) << "Candidate gathering is complete.";
-    OnCandidatesAllocationDone();
-  }
+void BaseSession::SetIceConnectionReceivingTimeout(int timeout_ms) {
+  transport_controller_->SetIceConnectionReceivingTimeout(timeout_ms);
 }
 
-void BaseSession::OnRoleConflict() {
-  if (role_switch_) {
-    LOG(LS_WARNING) << "Repeat of role conflict signal from Transport.";
-    return;
-  }
-
-  role_switch_ = true;
-  for (TransportMap::iterator iter = transports_.begin();
-       iter != transports_.end(); ++iter) {
-    // Role will be reverse of initial role setting.
-    IceRole role = initiator_ ? ICEROLE_CONTROLLED : ICEROLE_CONTROLLING;
-    iter->second->SetIceRole(role);
-  }
+void BaseSession::MaybeStartGathering() {
+  transport_controller_->MaybeStartGathering();
 }
 
 void BaseSession::LogState(State old_state, State new_state) {
   LOG(LS_INFO) << "Session:" << id()
                << " Old state:" << StateToString(old_state)
-               << " New state:" << StateToString(new_state)
-               << " Type:" << content_type();
+               << " New state:" << StateToString(new_state);
 }
 
 // static