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..a263e7609966b249b30e26a4df021759ffca953b 100644
--- a/webrtc/p2p/base/p2ptransportchannel.cc
+++ b/webrtc/p2p/base/p2ptransportchannel.cc
@@ -310,6 +310,9 @@ TransportChannelState P2PTransportChannel::ComputeState() const {
 
 void P2PTransportChannel::SetIceParameters(const IceParameters& ice_params) {
   ASSERT(worker_thread_ == rtc::Thread::Current());
+  LOG(LS_INFO) << "Set ICE ufrag: "<< ice_params.ufrag
+               << " pwd: " << ice_params.pwd
+               << " on transport "<< transport_name();

[Taylor Brandstetter, 2016/09/14 20:39:04]

nit: Missing whitespace, can probably do git cl format

[honghaiz3, 2016/09/15 17:38:29]

Done.

   ice_parameters_ = ice_params;
   // Note: Candidate gathering will restart when MaybeStartGathering is next
   // called.
@@ -434,6 +437,9 @@ 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.