Revert of Separating SCTP code from BaseChannel/MediaChannel.

webrtc/api/webrtcsessiondescriptionfactory.cc

Index: webrtc/api/webrtcsessiondescriptionfactory.cc
diff --git a/webrtc/api/webrtcsessiondescriptionfactory.cc b/webrtc/api/webrtcsessiondescriptionfactory.cc
index 0ab458bdfea65af40401d2f8822fe1c1fef2b0d0..1f811f59117afd539e2349d5010c52fd0aa0fc22 100644
--- a/webrtc/api/webrtcsessiondescriptionfactory.cc
+++ b/webrtc/api/webrtcsessiondescriptionfactory.cc
@@ -400,7 +400,7 @@ void WebRtcSessionDescriptionFactory::InternalCreateAnswer(
       // We should pass the current SSL role to the transport description
       // factory, if there is already an existing ongoing session.
       rtc::SSLRole ssl_role;
-      if (session_->GetSslRole(content.name, &ssl_role)) {
+      if (session_->GetSslRole(session_->GetChannel(content.name), &ssl_role)) {
         request.options.transport_options[content.name].prefer_passive_role =
             (rtc::SSL_SERVER == ssl_role);
       }