Adding logs to track potential cause of not starting port allocation.

webrtc/p2p/base/p2ptransportchannel.cc

Index: webrtc/p2p/base/p2ptransportchannel.cc
diff --git a/webrtc/p2p/base/p2ptransportchannel.cc b/webrtc/p2p/base/p2ptransportchannel.cc
index f5f8a665aa51e90ee7d544c1257216378bbaf023..e8e852a25fd9be140e6059a8718afd2dd4aec0f0 100644
--- a/webrtc/p2p/base/p2ptransportchannel.cc
+++ b/webrtc/p2p/base/p2ptransportchannel.cc
@@ -434,6 +434,9 @@ const IceConfig& P2PTransportChannel::config() const {
 
 void P2PTransportChannel::MaybeStartGathering() {
   if (ice_parameters_.ufrag.empty() || ice_parameters_.pwd.empty()) {
+    LOG(LS_ERROR) << "Cannot gather candidates because ICE parameters are empty"
+                  << " ufrag: " << ice_parameters_.ufrag
+                  << " pwd: " << ice_parameters_.pwd;
     return;
   }
   // Start gathering if we never started before, or if an ICE restart occurred.