Accomodate files larger than maxint in size in blob/file reading.

webkit/blob/local_file_reader.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 WEBKIT_BLOB_LOCAL_FILE_READER_H_
 #define WEBKIT_BLOB_LOCAL_FILE_READER_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
@@ skipping 39 matching lines @@
   // Reads from the current cursor position asynchronously.
   // This works mostly same as how net::FileStream::Read() works except that
   // it internally opens (and seeks) the file if it is not opened yet.
   // It is invalid to call Read while there is an in-flight Read operation.
   int Read(net::IOBuffer* buf, int buf_len,
            const net::CompletionCallback& callback);
 
   // Returns the number of bytes available to read from the beginning of
   // the file (or initial_offset) until the end of the file (rv >= 0 cases).
   // Otherwise, a negative error code is returned (rv < 0 cases).
-  int GetLength(const net::CompletionCallback& callback);
+  int GetLength(const net::Int64CompletionCallback& callback);
 
  private:
   class OpenFileStreamHelper;
 
   int Open(const OpenFileStreamCallback& callback);
   void DidOpen(net::IOBuffer* buf,
                int buf_len,
                const net::CompletionCallback& callback,
                int open_error,
                scoped_ptr<net::FileStream> stream);
 
   scoped_refptr<base::MessageLoopProxy> file_thread_proxy_;
   scoped_ptr<net::FileStream> stream_impl_;
   const FilePath file_path_;
   const int64 initial_offset_;
   const base::Time expected_modification_time_;
   bool has_pending_open_;
   base::WeakPtrFactory<LocalFileReader> weak_factory_;
 };
 
 }  // namespace webkit_blob
 
 #endif  // WEBKIT_BLOB_LOCAL_FILE_READER_H_