Add LookupDtlsTransportByMid to proxy map

Bug: chromium:907849
Change-Id: Ib707f18fdf67617967b83cd17f0454d182b8011f
Reviewed-on: https://webrtc-review.googlesource.com/c/112907
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25885}
diff --git a/api/peerconnectioninterface.h b/api/peerconnectioninterface.h
index 02b925d..4a7b051 100644
--- a/api/peerconnectioninterface.h
+++ b/api/peerconnectioninterface.h
@@ -1034,9 +1034,9 @@
   // In the Javascript API, DtlsTransport is a property of a sender, but
   // because the PeerConnection owns the DtlsTransport in this implementation,
   // it is better to look them up on the PeerConnection.
+  // TODO(hta): Remove default implementation after updating Chrome.
   virtual rtc::scoped_refptr<DtlsTransportInterface> LookupDtlsTransportByMid(
       const std::string& mid);
-  // TODO(hta): Remove default implementation.
 
   // Returns the current SignalingState.
   virtual SignalingState signaling_state() = 0;