Dampening connection switch.

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 14cda683f5bf499358c0d77cf7220464e9553745..4a414ef1bbb1d0b071094dabbf78288e998a3dbc 100644
--- a/webrtc/p2p/base/p2ptransportchannel.h
+++ b/webrtc/p2p/base/p2ptransportchannel.h
@@ -208,7 +208,7 @@ class P2PTransportChannel : public TransportChannelImpl,
   }
 
  private:
-  rtc::Thread* thread() { return worker_thread_; }
+  rtc::Thread* thread() const { return worker_thread_; }
   bool IsGettingPorts() { return allocator_session()->IsGettingPorts(); }
 
   // A transport channel is weak if the current best connection is either
@@ -222,10 +222,16 @@ class P2PTransportChannel : public TransportChannelImpl,
   // that's pingable.
   void MaybeStartPinging();
 
-  // The methods below return a positive value if a is preferable to b,
-  // a negative value if b is preferable, and 0 if they're equally preferable.
+  // The methods below return a positive value if |a| is preferable to |b|,
+  // a negative value if |b| is preferable, and 0 if they're equally preferable.
+  // If |b_receiving_threshold| is not zero, then when |b| is receiving and |a|
+  // is not, returns a negative value only if the current time is at least
+  // |b_receiving_threshold| milliseconds. If the current time is less than
+  // that, sets |switching_dampened| to be true.

[pthatcher1, 2016/07/14 18:01:44]

to be true => to true

Also, "switching_dampened" might be better named "b_missed_recieving_threshold"

[honghaiz3, 2016/07/14 23:15:01]

Done.

   int CompareConnectionStates(const cricket::Connection* a,
-                              const cricket::Connection* b) const;
+                              const cricket::Connection* b,
+                              int64_t b_receiving_threshold,
+                              bool* switching_dampened) const;
   int CompareConnectionCandidates(const cricket::Connection* a,
                                   const cricket::Connection* b) const;
   // Compares two connections based on the connection states
@@ -234,12 +240,12 @@ class P2PTransportChannel : public TransportChannelImpl,
   // and ShouldSwitchSelectedConnection().
   // Returns a positive value if |a| is better than |b|.
   int CompareConnections(const cricket::Connection* a,
-                         const cricket::Connection* b) const;
+                         const cricket::Connection* b,
+                         int64_t b_receiving_threshold,
+                         bool* switching_dampened) const;
 
   bool PresumedWritable(const cricket::Connection* conn) const;
 
-  bool ShouldSwitchSelectedConnection(const cricket::Connection* selected,
-                                      const cricket::Connection* conn) const;
   void SortConnectionsAndUpdateState();
   void SwitchSelectedConnection(Connection* conn);
   void UpdateState();
@@ -307,7 +313,7 @@ class P2PTransportChannel : public TransportChannelImpl,
   void OnRegatherOnFailedNetworks();
 
   // Returns true if the new_connection should be selected for transmission.
-  bool ShouldSwitchSelectedConnection(Connection* new_connection) const;
+  bool ShouldSwitchSelectedConnection(Connection* new_connection);
 
   void PruneConnections();
   bool IsBackupConnection(const Connection* conn) const;
@@ -387,6 +393,7 @@ class P2PTransportChannel : public TransportChannelImpl,
   IceConfig config_;
   int last_sent_packet_id_ = -1;  // -1 indicates no packet was sent before.
   bool started_pinging_ = false;
+  bool was_strong_ = false;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(P2PTransportChannel);
 };