Revert of Modified PeerConnection and WebRtcSession for end-to-end QuicDataChannel usage.

webrtc/api/peerconnection.cc

Index: webrtc/api/peerconnection.cc
diff --git a/webrtc/api/peerconnection.cc b/webrtc/api/peerconnection.cc
index 95cd7ea179f6cc89806610e1dc53aa2514d06506..4ccd6e83adef931dac9d4cc9f1da853024670a6b 100644
--- a/webrtc/api/peerconnection.cc
+++ b/webrtc/api/peerconnection.cc
@@ -907,23 +907,6 @@
     const std::string& label,
     const DataChannelInit* config) {
   TRACE_EVENT0("webrtc", "PeerConnection::CreateDataChannel");
-#ifdef HAVE_QUIC
-  if (session_->data_channel_type() == cricket::DCT_QUIC) {
-    // TODO(zhihuang): Handle case when config is NULL.
-    if (!config) {
-      LOG(LS_ERROR) << "Missing config for QUIC data channel.";
-      return nullptr;
-    }
-    // TODO(zhihuang): Allow unreliable or ordered QUIC data channels.
-    if (!config->reliable || config->ordered) {
-      LOG(LS_ERROR) << "QUIC data channel does not implement unreliable or "
-                       "ordered delivery.";
-      return nullptr;
-    }
-    return session_->quic_data_transport()->CreateDataChannel(label, config);
-  }
-#endif  // HAVE_QUIC
-
   bool first_datachannel = !HasDataChannels();
 
   std::unique_ptr<InternalDataChannelInit> internal_config;
@@ -1635,8 +1618,8 @@
       (session_options->has_audio() || session_options->has_video() ||
        session_options->has_data());
 
-  if (HasDataChannels()) {
-    session_options->data_channel_type = session_->data_channel_type();
+  if (session_->data_channel_type() == cricket::DCT_SCTP && HasDataChannels()) {
+    session_options->data_channel_type = cricket::DCT_SCTP;
   }
 
   session_options->rtcp_cname = rtcp_cname_;
@@ -1665,7 +1648,9 @@
   // RTP data channel is handled in MediaSessionOptions::AddStream. SCTP streams
   // are not signaled in the SDP so does not go through that path and must be
   // handled here.
-  session_options->data_channel_type = session_->data_channel_type();
+  if (session_->data_channel_type() == cricket::DCT_SCTP) {
+    session_options->data_channel_type = cricket::DCT_SCTP;
+  }
   session_options->crypto_options = factory_->options().crypto_options;
 }
 
@@ -2069,13 +2054,7 @@
 }
 
 bool PeerConnection::HasDataChannels() const {
-#ifdef HAVE_QUIC
-  return !rtp_data_channels_.empty() || !sctp_data_channels_.empty() ||
-         (session_->quic_data_transport() &&
-          session_->quic_data_transport()->HasDataChannels());
-#else
   return !rtp_data_channels_.empty() || !sctp_data_channels_.empty();
-#endif  // HAVE_QUIC
 }
 
 void PeerConnection::AllocateSctpSids(rtc::SSLRole role) {