Keep on sending stun binding requests on zero-cost networks.

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 ecf61a782dfc13ad2d3e64df48dbaa45c5c51324..2ab6048c50230506669fb49012b32dce72dc28c6 100644
--- a/webrtc/p2p/base/stunport.h
+++ b/webrtc/p2p/base/stunport.h
@@ -106,6 +106,14 @@ class UDPPort : public Port {
     return stun_keepalive_delay_;
   }
 
+  // Visible for testing.
+  int stun_keepalive_lifetime() const { return stun_keepalive_lifetime_; }
+  void set_stun_keepalive_lifetime(int lifetime) {
+    stun_keepalive_lifetime_ = lifetime;
+  }
+  // Returns true if there is a pending request with type |msg_type|.
+  bool RequestExists(int msg_type) { return requests_.Exist(msg_type); }

[pthatcher1, 2016/03/02 20:25:59]

A better name might be HasPendingRequest

[honghaiz3, 2016/03/02 23:22:51]

Done.

+
  protected:
   UDPPort(rtc::Thread* thread,
           rtc::PacketSocketFactory* factory,
@@ -217,6 +225,7 @@ class UDPPort : public Port {
   rtc::scoped_ptr<AddressResolver> resolver_;
   bool ready_;
   int stun_keepalive_delay_;
+  int stun_keepalive_lifetime_;
 
   // This is true by default and false when
   // PORTALLOCATOR_DISABLE_DEFAULT_LOCAL_CANDIDATE is specified.