RTCStatsCollector: Utilize network thread to minimize thread hops.

webrtc/p2p/base/transportcontroller.cc

Index: webrtc/p2p/base/transportcontroller.cc
diff --git a/webrtc/p2p/base/transportcontroller.cc b/webrtc/p2p/base/transportcontroller.cc
index 4b24b1990d205a1ae12ec6cf87015ee50cf17822..de8434c83adac511e1e67c1e939719dbc443ec4f 100644
--- a/webrtc/p2p/base/transportcontroller.cc
+++ b/webrtc/p2p/base/transportcontroller.cc
@@ -112,6 +112,8 @@ bool TransportController::SetLocalCertificate(
 bool TransportController::GetLocalCertificate(
     const std::string& transport_name,
     rtc::scoped_refptr<rtc::RTCCertificate>* certificate) const {
+  if (network_thread_->IsCurrent())
+    return GetLocalCertificate_n(transport_name, certificate);
   return network_thread_->Invoke<bool>(
       RTC_FROM_HERE, rtc::Bind(&TransportController::GetLocalCertificate_n,
                                this, transport_name, certificate));
@@ -120,6 +122,8 @@ bool TransportController::GetLocalCertificate(
 std::unique_ptr<rtc::SSLCertificate>
 TransportController::GetRemoteSSLCertificate(
     const std::string& transport_name) const {
+  if (network_thread_->IsCurrent())
+    return GetRemoteSSLCertificate_n(transport_name);
   return network_thread_->Invoke<std::unique_ptr<rtc::SSLCertificate>>(
       RTC_FROM_HERE, rtc::Bind(&TransportController::GetRemoteSSLCertificate_n,
                                this, transport_name));
@@ -177,6 +181,8 @@ bool TransportController::ReadyForRemoteCandidates(
 
 bool TransportController::GetStats(const std::string& transport_name,
                                    TransportStats* stats) {
+  if (network_thread_->IsCurrent())
+    return GetStats_n(transport_name, stats);
   return network_thread_->Invoke<bool>(
       RTC_FROM_HERE,
       rtc::Bind(&TransportController::GetStats_n, this, transport_name, stats));