Ping connections with the fast rate until each connection is pinged at least three times.

webrtc/p2p/base/p2ptransportchannel.h

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 21 matching lines @@
 #include "webrtc/p2p/base/p2ptransport.h"
 #include "webrtc/p2p/base/portallocator.h"
 #include "webrtc/p2p/base/portinterface.h"
 #include "webrtc/p2p/base/transportchannelimpl.h"
 #include "webrtc/base/asyncpacketsocket.h"
 #include "webrtc/base/sigslot.h"
 
 namespace cricket {
 
 extern const int WEAK_PING_INTERVAL;
+static const int kMinNumPingsSent = 3;

[pthatcher1, 2016/05/25 17:29:13]

Can we keep the same style?  And a slightly better name might be
MIN_PINGS_AT_WEAK_PING_INTERVAL

[honghaiz3, 2016/05/25 18:40:02]

Done.

 
 struct IceParameters {
   std::string ufrag;
   std::string pwd;
   IceParameters(const std::string& ice_ufrag, const std::string& ice_pwd)
       : ufrag(ice_ufrag), pwd(ice_pwd) {}
 
   bool operator==(const IceParameters& other) {
     return ufrag == other.ufrag && pwd == other.pwd;
   }
@@ skipping 279 matching lines @@
   TransportChannelState state_ = TransportChannelState::STATE_INIT;
   IceConfig config_;
   int last_sent_packet_id_ = -1;  // -1 indicates no packet was sent before.
 
   RTC_DISALLOW_COPY_AND_ASSIGN(P2PTransportChannel);
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_P2P_BASE_P2PTRANSPORTCHANNEL_H_