Make HostController/DeviceListener deletion fully synchronous.

tools/android/forwarder2/forwarder.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef TOOLS_ANDROID_FORWARDER2_FORWARDER_H_
 #define TOOLS_ANDROID_FORWARDER2_FORWARDER_H_
 
+#include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/threading/thread.h"
+#include "tools/android/forwarder2/self_deleter_helper.h"
 
 namespace forwarder2 {
 
+class PipeNotifier;
 class Socket;
 
-void StartForwarder(scoped_ptr<Socket> socket1, scoped_ptr<Socket> socket2);
+// Internal class that wraps a helper thread to forward traffic between
+// |socket1| and |socket2|. After creating a new instance, call its Start()
+// method to launch operations. Thread stops automatically if one of the socket
+// disconnects, but ensures that all buffered writes to the other, still alive,
+// socket, are written first. When this happens, the instance will delete itself
+// automatically.
+// Note that the instance will always be destroyed on the same thread that
+// created it.
+class Forwarder {
+ public:
+  // Callback used on error invoked by the Forwarder to self-delete.
+  typedef base::Callback<void (scoped_ptr<Forwarder>)> ErrorCallback;
+
+  Forwarder(scoped_ptr<Socket> socket1,
+            scoped_ptr<Socket> socket2,
+            PipeNotifier* deletion_notifier,
+            const ErrorCallback& error_callback);
+
+  ~Forwarder();
+
+  void Start();
+
+ private:
+  void ThreadHandler();
+
+  void OnThreadHandlerCompletion(const ErrorCallback& error_callback);
+
+  SelfDeleterHelper<Forwarder> self_deleter_helper_;
+  PipeNotifier* const deletion_notifier_;
+  scoped_ptr<Socket> socket1_;
+  scoped_ptr<Socket> socket2_;
+  base::Thread thread_;
+};
 
 }  // namespace forwarder2
 
 #endif  // TOOLS_ANDROID_FORWARDER2_FORWARDER_H_