Add logs when stun or turn host lookup is completed.

webrtc/p2p/base/stunport.cc

Index: webrtc/p2p/base/stunport.cc
diff --git a/webrtc/p2p/base/stunport.cc b/webrtc/p2p/base/stunport.cc
index 93d95efce5659d6bfc8598d6617cba7a891f00a0..f99965bd72ee6672c46f2c37b35445dd425e1637 100644
--- a/webrtc/p2p/base/stunport.cc
+++ b/webrtc/p2p/base/stunport.cc
@@ -363,6 +363,8 @@ void UDPPort::ResolveStunAddress(const rtc::SocketAddress& stun_addr) {
     resolver_->SignalDone.connect(this, &UDPPort::OnResolveResult);
   }
 
+  LOG_J(LS_INFO, this) << "Starting STUN host lookup for "
+                       << stun_addr.ToSensitiveString();
   resolver_->Resolve(stun_addr);
 }