Make it possible to keep the port allocator session running

webrtc/p2p/base/p2ptransportchannel.cc

 /*
  *  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 1052 matching lines @@
       break;
     }
   }
   set_receiving(receiving);
 }
 
 // We checked the status of our connections and we had at least one that
 // was writable, go into the writable state.
 void P2PTransportChannel::HandleWritable() {
   ASSERT(worker_thread_ == rtc::Thread::Current());
   if (!writable()) {

[pthatcher1, 2015/09/28 23:34:00]

Can you make an early return here?

if (writable()) {
  return;
}

[honghaiz3, 2015/09/29 00:04:49]

Done.

     for (uint32 i = 0; i < allocator_sessions_.size(); ++i) {
-      if (allocator_sessions_[i]->IsGettingPorts()) {
-        allocator_sessions_[i]->StopGettingPorts();
+      PortAllocatorSession* session = allocator_sessions_[i];
+      if (!session->IsGettingPorts()) {
+        continue;
+      }
+      // If gathering continually, keep the last session running so that it
+      // will gather candidates if the networks change.
+      if (gather_continually_ && (i + 1 == allocator_sessions_.size())) {
+        session->ClearGettingPorts();
+      } else {
+        session->StopGettingPorts();
       }

[pthatcher1, 2015/09/28 23:34:00]

I think this would be more readable like this:
 
  for (PortAllocactorSession* session : allocator_sessions_) {
    if (!session->IsGettingPorts()) {
      continue;
    }
    if (gather_continually && session == allocator_sessions_.back()) {
      // If gathering continually, keep the last session running so that it
      // will gather candidates if the networks change.
      session->ClearGettingPorts();
      continue;
    }
    session->StopGettingPorts();
  }

[honghaiz3, 2015/09/29 00:04:49]

Done. Replaced continue with break because that is the last session. 

     }
   }
 
   was_writable_ = true;
   set_writable(true);
 }
 
 // Notify upper layer about channel not writable state, if it was before.
 void P2PTransportChannel::HandleNotWritable() {
   ASSERT(worker_thread_ == rtc::Thread::Current());
@@ skipping 257 matching lines @@
   }
 }
 
 void P2PTransportChannel::OnReadyToSend(Connection* connection) {
   if (connection == best_connection_ && writable()) {
     SignalReadyToSend(this);
   }
 }
 
 }  // namespace cricket