Move fileapi into its own component

webkit/fileapi/file_system_usage_cache.h

 // Copyright (c) 2011 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_FILEAPI_FILE_SYSTEM_USAGE_CACHE_H_
 #define WEBKIT_FILEAPI_FILE_SYSTEM_USAGE_CACHE_H_
 
 #include "base/basictypes.h"
 #include "base/file_path.h"
+#include "webkit/fileapi/fileapi_export.h"
 
 namespace fileapi {
 
-class FileSystemUsageCache {
+class FILEAPI_EXPORT_PRIVATE FileSystemUsageCache {
  public:
   // Gets the size described in the .usage file even if dirty > 0 or
   // is_valid == false.  Returns less than zero if the .usage file is not
   // available.
   static int64 GetUsage(const FilePath& usage_file_path);
 
   // Gets the dirty count in the .usage file.
   // Returns less than zero if the .usage file is not available.
   static int32 GetDirty(const FilePath& usage_file_path);
 
@@ skipping 32 matching lines @@
 
   static int Write(const FilePath& usage_file_path,
                    bool is_valid,
                    uint32 dirty,
                    int64 fs_usage);
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_USAGE_CACHE_H_