Signal ready-to-send when switching to a writable connection.

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 1145 matching lines @@
   Connection* old_best_connection = best_connection_;
   best_connection_ = conn;
   if (best_connection_) {
     if (old_best_connection) {
       LOG_J(LS_INFO, this) << "Previous best connection: "
                            << old_best_connection->ToString();
     }
     LOG_J(LS_INFO, this) << "New best connection: "
                          << best_connection_->ToString();
     SignalRouteChange(this, best_connection_->remote_candidate());
+    // This is a temporary, but safe fix to webrtc issue 5705.
+    // TODO(honghaiz): Make all EWOULDBLOCK error routed through the transport
+    // channel so that it knows whether the media channel is allowed to
+    // send; then it will only signal ready-to-send if the media channel
+    // has been disallowed to send.
+    if (best_connection_->writable()) {
+      SignalReadyToSend(this);
+    }
   } else {
     LOG_J(LS_INFO, this) << "No best connection";
   }
   // TODO(honghaiz): rename best_connection_ with selected_connection_ or
   // selected_candidate pair_.
   SignalSelectedCandidatePairChanged(this, best_connection_);
 }
 
 // Warning: UpdateState should eventually be called whenever a connection
 // is added, deleted, or the write state of any connection changes so that the
@@ skipping 447 matching lines @@
 
   // During the initial state when nothing has been pinged yet, return the first
   // one in the ordered |connections_|.
   return *(std::find_if(connections_.begin(), connections_.end(),
                         [conn1, conn2](Connection* conn) {
                           return conn == conn1 || conn == conn2;
                         }));
 }
 
 }  // namespace cricket