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 01394a97aaf19e6cce628e07b157c22b59abf458..4a3a00e10f0e2831e4eefcf6bd53d229086b0d84 100644
--- a/webrtc/p2p/base/transportcontroller.cc
+++ b/webrtc/p2p/base/transportcontroller.cc
@@ -141,6 +141,9 @@ 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));
@@ -149,6 +152,9 @@ 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));
@@ -206,6 +212,9 @@ 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));