Reland "Create RTCIceTransport using a webrtc::IceTransportInterface object."

This is a reland of dd0f551fcd96d46c6ec2b2a7c543cb2083f1831d

Original change's description:
> Create RTCIceTransport using a webrtc::IceTransportInterface object.
>
> Previously, when creating a blink::RTCIceTransport, the corresponding
> webrtc::IceTransportInterface object was created by the
> IceTransportAdapterImpl. However, in DTLS transport implementation, the
> webrtc object is preexisting. Pass the preexisting webrtc object when creating
> the blink::RTCIceTransport object in this case.
>
> Bug: 907849
> Change-Id: Ia024afc101be830e30f233d6ef1bf39f141227df
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1520486
> Commit-Queue: Marina Ciocea <marinaciocea@chromium.org>
> Reviewed-by: Harald Alvestrand <hta@chromium.org>
> Reviewed-by: Henrik Boström <hbos@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#642487}

Bug: 907849
Change-Id: Ib428f33faae0563d12d246bc971e38f9a66d629a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1533896
Commit-Queue: Marina Ciocea <marinaciocea@chromium.org>
Reviewed-by: Henrik Boström <hbos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#643321}
diff --git a/webrtc/RTCPeerConnection-iceConnectionState.https.html b/webrtc/RTCPeerConnection-iceConnectionState.https.html
index 8acabf4..768da23 100644
--- a/webrtc/RTCPeerConnection-iceConnectionState.https.html
+++ b/webrtc/RTCPeerConnection-iceConnectionState.https.html
@@ -148,21 +148,21 @@
       const { iceConnectionState } = pc1;
 
       if(iceConnectionState === 'checking') {
-        const iceTransport = pc1.sctp.transport.transport;
+        const iceTransport = pc1.sctp.transport.iceTransport;
 
         assert_equals(iceTransport.state, 'checking',
           'Expect ICE transport to be in checking state when' +
           ' iceConnectionState is checking');
 
       } else if(iceConnectionState === 'connected') {
-        const iceTransport = pc1.sctp.transport.transport;
+        const iceTransport = pc1.sctp.transport.iceTransport;
 
         assert_equals(iceTransport.state, 'connected',
           'Expect ICE transport to be in connected state when' +
           ' iceConnectionState is connected');
 
       } else if(iceConnectionState === 'completed') {
-        const iceTransport = pc1.sctp.transport.transport;
+        const iceTransport = pc1.sctp.transport.iceTransport;
 
         assert_equals(iceTransport.state, 'completed',
           'Expect ICE transport to be in connected state when' +
diff --git a/webrtc/RTCPeerConnection-iceGatheringState.html b/webrtc/RTCPeerConnection-iceGatheringState.html
index e6d8d06..e170e4a 100644
--- a/webrtc/RTCPeerConnection-iceGatheringState.html
+++ b/webrtc/RTCPeerConnection-iceGatheringState.html
@@ -108,13 +108,13 @@
       const { iceGatheringState } = pc2;
 
       if(iceGatheringState === 'gathering') {
-        const iceTransport = pc2.sctp.transport.transport;
+        const iceTransport = pc2.sctp.transport.iceTransport;
 
         assert_equals(iceTransport.gatheringState, 'gathering',
           'Expect ICE transport to be in checking gatheringState when iceGatheringState is checking');
 
       } else if(iceGatheringState === 'complete') {
-        const iceTransport = pc2.sctp.transport.transport;
+        const iceTransport = pc2.sctp.transport.iceTransport;
 
         assert_equals(iceTransport.gatheringState, 'complete',
           'Expect ICE transport to be in complete gatheringState when iceGatheringState is complete');