Revert "Revert of Update the BWE when the network route changes. (patchset #5 id:180001 of https://…

webrtc/p2p/base/port.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 466 matching lines @@
 
   // The connection can send and receive packets asynchronously.  This matches
   // the interface of AsyncPacketSocket, which may use UDP or TCP under the
   // covers.
   virtual int Send(const void* data, size_t size,
                    const rtc::PacketOptions& options) = 0;
 
   // Error if Send() returns < 0
   virtual int GetError() = 0;
 
+  virtual bool ReadyToSendMedia() const {

[pthatcher1, 2016/06/08 18:26:39]

Why not just connected()?

[honghaiz3, 2016/06/08 18:36:42]

connected() has already been used in the class.

[pthatcher1, 2016/06/08 18:46:58]

Ah, now you make me realize that this is almost the same as writable().   We're
just distinguishing between weakly and strongly writable.  Does it really matter
for the BWE?  Could we just use writable() instead of adding a new one?

Having connected, writable, and ReadyToSendMedia is getting to be a bit too many
things.

[honghaiz3, 2016/06/09 16:37:34]

See my reply in the email (and the post of this change). 
Plus, this does not add new state, just a method derived from the write_state_.
I put it along with other convenience methods relying on write_state_.  

+    return write_state_ == STATE_WRITABLE ||
+           write_state_ == STATE_WRITE_UNRELIABLE;
+  }
+
   sigslot::signal4<Connection*, const char*, size_t, const rtc::PacketTime&>
       SignalReadPacket;
 
   sigslot::signal1<Connection*> SignalReadyToSend;
 
   // Called when a packet is received on this connection.
   void OnReadPacket(const char* data, size_t size,
                     const rtc::PacketTime& packet_time);
 
   // Called when the socket is currently able to send.
@@ skipping 168 matching lines @@
            const rtc::PacketOptions& options) override;
   int GetError() override { return error_; }
 
  private:
   int error_ = 0;
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_P2P_BASE_PORT_H_