Allow passing both hostname and IP of ICE server into PeerConnection.

webrtc/api/peerconnectioninterface.h

Index: webrtc/api/peerconnectioninterface.h
diff --git a/webrtc/api/peerconnectioninterface.h b/webrtc/api/peerconnectioninterface.h
index 8ff7e1e469c7805e84eed4a0ec2eadb1c5874a23..d692cea3225fae48261db82381aa30b06b399b4b 100644
--- a/webrtc/api/peerconnectioninterface.h
+++ b/webrtc/api/peerconnectioninterface.h
@@ -181,6 +181,9 @@ class PeerConnectionInterface : public rtc::RefCountInterface {
     std::string username;
     std::string password;
     TlsCertPolicy tls_cert_policy = kTlsCertPolicySecure;
+    // Optional; can be used if the IP address of this server was resolved
+    // ahead of time, so that webrtc doesn't need to do a redundant lookup.
+    rtc::IPAddress ip;
 
     bool operator==(const IceServer& o) const {
       return uri == o.uri && urls == o.urls && username == o.username &&