[fsp] Improve performance for reading small chunks of data.

content/public/test/test_file_system_backend.h

 // Copyright 2013 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 CONTENT_PUBLIC_TEST_TEST_FILE_SYSTEM_BACKEND_H_
 #define CONTENT_PUBLIC_TEST_TEST_FILE_SYSTEM_BACKEND_H_
 
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 38 matching lines @@
       const fileapi::FileSystemURL& url,
       fileapi::FileSystemContext* context,
       base::File::Error* error_code) const OVERRIDE;
   virtual bool SupportsStreaming(
       const fileapi::FileSystemURL& url) const OVERRIDE;
   virtual bool HasInplaceCopyImplementation(
       fileapi::FileSystemType type) const OVERRIDE;
   virtual scoped_ptr<webkit_blob::FileStreamReader> CreateFileStreamReader(
       const fileapi::FileSystemURL& url,
       int64 offset,
+      int64 length,
       const base::Time& expected_modification_time,
       fileapi::FileSystemContext* context) const OVERRIDE;
   virtual scoped_ptr<fileapi::FileStreamWriter> CreateFileStreamWriter(
       const fileapi::FileSystemURL& url,
       int64 offset,
       fileapi::FileSystemContext* context) const OVERRIDE;
   virtual fileapi::FileSystemQuotaUtil* GetQuotaUtil() OVERRIDE;
 
   // Initialize the CopyOrMoveFileValidatorFactory. Invalid to call more than
   // once.
@@ skipping 22 matching lines @@
   bool require_copy_or_move_validator_;
   scoped_ptr<fileapi::CopyOrMoveFileValidatorFactory>
       copy_or_move_file_validator_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TestFileSystemBackend);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_TEST_FILE_SYSTEM_BACKEND_H_