Stop sending stun binding requests after certain amount of time.

webrtc/p2p/base/stunport.h

Index: webrtc/p2p/base/stunport.h
diff --git a/webrtc/p2p/base/stunport.h b/webrtc/p2p/base/stunport.h
index ccd3f36cc304678dba9e4120f737e1c319666b5b..9e2c14c531ad05173595a88f816a69cf05d87d3a 100644
--- a/webrtc/p2p/base/stunport.h
+++ b/webrtc/p2p/base/stunport.h
@@ -205,6 +205,8 @@ class UDPPort : public Port {
 
   bool HasCandidateWithAddress(const rtc::SocketAddress& addr) const;
 
+  uint32_t start_time() { return start_time_; }
+
   ServerAddresses server_addresses_;
   ServerAddresses bind_request_succeeded_servers_;
   ServerAddresses bind_request_failed_servers_;
@@ -214,6 +216,7 @@ class UDPPort : public Port {
   rtc::scoped_ptr<AddressResolver> resolver_;
   bool ready_;
   int stun_keepalive_delay_;
+  uint32_t start_time_;
 
   // This is true by default and false when
   // PORTALLOCATOR_DISABLE_DEFAULT_LOCAL_CANDIDATE is specified.