A few updates on connection states

webrtc/p2p/base/p2ptransportchannel.h

Index: webrtc/p2p/base/p2ptransportchannel.h
diff --git a/webrtc/p2p/base/p2ptransportchannel.h b/webrtc/p2p/base/p2ptransportchannel.h
index a8f16666c9625897de4cff8e9f0e11a86c76d13e..92dc3c4a5fc7470557aa411e61e90d4ca47e1343 100644
--- a/webrtc/p2p/base/p2ptransportchannel.h
+++ b/webrtc/p2p/base/p2ptransportchannel.h
@@ -165,6 +165,9 @@ class P2PTransportChannel : public TransportChannelImpl,
     return allocator_sessions_.back();
   }
 
+  // A transport channel is weak if the current best connection is either
+  // not receiving or not writable, or if there is no best connection at all.
+  bool Weak() const;
   void Allocate();
   void UpdateConnectionStates();
   void RequestSort();
@@ -215,9 +218,7 @@ class P2PTransportChannel : public TransportChannelImpl,
 
   void OnMessage(rtc::Message *pmsg) override;
   void OnSort();
-  void OnPing();
-
-  void OnCheckReceiving();
+  void OnCheckAndPing();
 
   void PruneConnections();
   Connection* best_nominated_connection() const;
@@ -251,6 +252,7 @@ class P2PTransportChannel : public TransportChannelImpl,
 
   int check_receiving_delay_;
   int receiving_timeout_;
+  uint32 last_ping_sent_ms_ = 0;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(P2PTransportChannel);
 };