Remove some PlatformFile instances from ChromeOS Drive.

net/base/file_stream_context.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.
 
 // This file defines FileStream::Context class.
 // The general design of FileStream is as follows: file_stream.h defines
 // FileStream class which basically is just an "wrapper" not containing any
 // specific implementation details. It re-routes all its method calls to
 // the instance of FileStream::Context (FileStream holds a scoped_ptr to
 // FileStream::Context instance). Context was extracted into a different class
@@ skipping 150 matching lines @@
 
   OpenResult OpenFileImpl(const base::FilePath& path, int open_flags);
 
   IOResult CloseFileImpl();
 
   void ProcessOpenError(const IOResult& result);
   void OnOpenCompleted(const CompletionCallback& callback,
                        OpenResult open_result);
 
   void CloseAndDelete();
-  void OnCloseCompleted();
 
   Int64CompletionCallback IntToInt64(const CompletionCallback& callback);
 
   // Called when asynchronous Seek() is completed.
   // Reports error if needed and calls callback.
   void ProcessAsyncResult(const Int64CompletionCallback& callback,
                           FileErrorSource source,
                           const IOResult& result);
 
   // Called when asynchronous Open() or Seek()
@@ skipping 60 matching lines @@
   FileErrorSource error_source_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(Context);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_FILE_STREAM_CONTEXT_H_