Adding comment about ice_connection_state really being ICE+DTLS.

NOTRY=True
TBR=zhihuang@webrtc.org

Bug: webrtc:6145
Change-Id: I02c75ddd96007d942cc4d3ee8313691cf0be6827
Reviewed-on: https://webrtc-review.googlesource.com/14560
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Commit-Queue: Taylor Brandstetter <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20379}
diff --git a/api/peerconnectioninterface.h b/api/peerconnectioninterface.h
index 839b0f4..4ebb614 100644
--- a/api/peerconnectioninterface.h
+++ b/api/peerconnectioninterface.h
@@ -796,7 +796,13 @@
 
   // Returns the current SignalingState.
   virtual SignalingState signaling_state() = 0;
+
+  // Returns the aggregate state of all ICE *and* DTLS transports.
+  // TODO(deadbeef): Implement "PeerConnectionState" according to the standard,
+  // to aggregate ICE+DTLS state, and change the scope of IceConnectionState to
+  // be just the ICE layer. See: crbug.com/webrtc/6145
   virtual IceConnectionState ice_connection_state() = 0;
+
   virtual IceGatheringState ice_gathering_state() = 0;
 
   // Starts RtcEventLog using existing file. Takes ownership of |file| and