Delete unused class AsyncFile.

webrtc/base/asyncfile.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.
- */
-
-#ifndef WEBRTC_BASE_ASYNCFILE_H__
-#define WEBRTC_BASE_ASYNCFILE_H__
-
-#include "webrtc/base/sigslot.h"
-
-namespace rtc {
-
-// Provides the ability to perform file I/O asynchronously.
-// TODO: Create a common base class with AsyncSocket.
-class AsyncFile {
- public:
-  AsyncFile();
-  virtual ~AsyncFile();
-
-  // Determines whether the file will receive read events.
-  virtual bool readable() = 0;
-  virtual void set_readable(bool value) = 0;
-
-  // Determines whether the file will receive write events.
-  virtual bool writable() = 0;
-  virtual void set_writable(bool value) = 0;
-
-  sigslot::signal1<AsyncFile*> SignalReadEvent;
-  sigslot::signal1<AsyncFile*> SignalWriteEvent;
-  sigslot::signal2<AsyncFile*, int> SignalCloseEvent;
-};
-
-}  // namespace rtc
-
-#endif  // WEBRTC_BASE_ASYNCFILE_H__