Revert of Remove the obsolete enum webrtc::PeerConnectionInterface::IceState.

webrtc/api/peerconnection.h

Index: webrtc/api/peerconnection.h
diff --git a/webrtc/api/peerconnection.h b/webrtc/api/peerconnection.h
index a777c726297e05bd25cc9ce16f8e602b99bbbc17..c4a9a60053db82ca9976340412334e70bae55a59 100644
--- a/webrtc/api/peerconnection.h
+++ b/webrtc/api/peerconnection.h
@@ -105,6 +105,8 @@
 
   SignalingState signaling_state() override;
 
+  // TODO(bemasc): Remove ice_state() when callers are removed.
+  IceState ice_state() override;
   IceConnectionState ice_connection_state() override;
   IceGatheringState ice_gathering_state() override;
 
@@ -379,6 +381,8 @@
   PeerConnectionObserver* observer_;
   UMAObserver* uma_observer_;
   SignalingState signaling_state_;
+  // TODO(bemasc): Remove ice_state_.
+  IceState ice_state_;
   IceConnectionState ice_connection_state_;
   IceGatheringState ice_gathering_state_;