Revert of Modify PeerConnection for end-to-end QuicDataChannel usage (patchset #4 id:60001 of https://codereview.webrtc.org/2089553002/ )

Reason for revert:
Reverting because description was inaccurate. Will reland after updating description.

Original issue's description:
> Modify PeerConnection for end-to-end QuicDataChannel usage
>
> To allow end-to-end QuicDataChannel usage with a
> PeerConnection, RTCConfiguration has been modified to
> include a boolean for whether to do QUIC, since negotiation of
> QUIC is not implemented. If one peer does QUIC, then it will be
> assumed that the other peer must do QUIC or the connection
> will fail.
>
> PeerConnection has been modified to create data channels of type
> QuicDataChannel when the peer wants to do QUIC.
>
> WebRtcSession has been modified to use a QuicTransportChannel
> instead of a DtlsTransportChannelWrapper/DataChannel
> when QUIC should be used.
>
> Modification of previous in-flight CL: https://codereview.chromium.org/1844803002/
>
> Committed: https://crrev.com/36c8d69ce188102ae6fd48c371cf1518f08698fb
> Cr-Commit-Position: refs/heads/master@{#13470}

TBR=pthatcher@webrtc.org,zhihuang@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review-Url: https://codereview.webrtc.org/2146133002
Cr-Commit-Position: refs/heads/master@{#13471}
diff --git a/webrtc/api/quicdatatransport_unittest.cc b/webrtc/api/quicdatatransport_unittest.cc
index 975898e..d668c55 100644
--- a/webrtc/api/quicdatatransport_unittest.cc
+++ b/webrtc/api/quicdatatransport_unittest.cc
@@ -64,9 +64,7 @@
 class QuicDataTransportPeer {
  public:
   QuicDataTransportPeer()
-      : quic_data_transport_(rtc::Thread::Current(),
-                             rtc::Thread::Current(),
-                             rtc::Thread::Current()),
+      : quic_data_transport_(rtc::Thread::Current(), rtc::Thread::Current()),
         ice_transport_channel_(new FakeTransportChannel("data", 0)),
         quic_transport_channel_(ice_transport_channel_) {
     ice_transport_channel_->SetAsync(true);
@@ -82,6 +80,8 @@
 
   // Connects |ice_transport_channel_| to that of the other peer.
   void Connect(QuicDataTransportPeer* other_peer) {
+    ice_transport_channel_->Connect();
+    other_peer->ice_transport_channel_->Connect();
     ice_transport_channel_->SetDestination(other_peer->ice_transport_channel_);
   }