Close all writers before JingleSession is destroyed.

remoting/protocol/host_control_sender.h

Index: remoting/protocol/host_control_sender.h
diff --git a/remoting/protocol/host_control_sender.h b/remoting/protocol/host_control_sender.h
index 2cce5987f6864300a9d28cd4e803523686f01dfc..a0eea33c0da798ae8d13f591b72c615873ad7eb3 100644
--- a/remoting/protocol/host_control_sender.h
+++ b/remoting/protocol/host_control_sender.h
@@ -27,9 +27,11 @@ namespace protocol {
 
 class BufferedSocketWriter;
 
+// Implementation of HostStub that sends commands on a socket. Must be
+// created and closed on the network thread, but can be used on any
+// other thread.
 class HostControlSender : public HostStub {
  public:
-  // Create a stub using a socket.
   explicit HostControlSender(net::Socket* socket);
   virtual ~HostControlSender();
 
@@ -38,6 +40,10 @@ class HostControlSender : public HostStub {
   virtual void BeginSessionRequest(
       const LocalLoginCredentials* credentials, Task* done);
 
+  // Stop writing. Must be called on the network thread when the
+  // underlying socket is being destroyed.
+  void Close();
+
  private:
   // Buffered socket writer holds the serialized message and send it on the
   // right thread.