Create ShareableFileReference on IO thread

webkit/fileapi/file_system_file_util_proxy.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_FILEAPI_FILE_SYSTEM_FILE_UTIL_PROXY_H_
 #define WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_PROXY_H_
 
 #include <vector>
 
 #include "base/callback.h"
 #include "base/file_path.h"
 #include "base/file_util_proxy.h"
 #include "base/memory/ref_counted.h"
 #include "base/platform_file.h"
 #include "base/tracked_objects.h"
+#include "webkit/fileapi/file_system_file_util.h"
 #include "webkit/fileapi/file_system_operation_interface.h"
 
 namespace fileapi {
 
 using base::PlatformFile;
 using base::PlatformFileError;
 using base::PlatformFileInfo;
 
 class FileSystemFileUtil;
 class FileSystemOperationContext;
 class FileSystemURL;
 
 // This class provides asynchronous access to FileSystemFileUtil methods for
 // FileSystem API operations.  This also implements cross-FileUtil copy/move
 // operations on top of FileSystemFileUtil methods.
 class FileSystemFileUtilProxy {
  public:
   // Some of the proxy routines are just wrapping around the FileUtilProxy's
   // relay methods, so we use the same types as FileUtilProxy for them.
   typedef base::FileUtilProxy::Entry Entry;
   typedef base::FileUtilProxy::CreateOrOpenCallback CreateOrOpenCallback;
 
   typedef base::Callback<void(PlatformFileError status)> StatusCallback;
   typedef base::Callback<void(PlatformFileError status,
                               bool created)> EnsureFileExistsCallback;
   typedef FileSystemOperationInterface::GetMetadataCallback GetFileInfoCallback;
-  typedef FileSystemOperationInterface::SnapshotFileCallback
-      SnapshotFileCallback;
   typedef FileSystemOperationInterface::ReadDirectoryCallback
       ReadDirectoryCallback;
 
+  typedef base::Callback<
+      void(base::PlatformFileError result,
+           const base::PlatformFileInfo& file_info,
+           const FilePath& platform_path,
+           FileSystemFileUtil::SnapshotFilePolicy snapshot_policy)>
+      SnapshotFileCallback;
+
   // Deletes a file or a directory on the given context's file_task_runner.
   // It is an error to delete a non-empty directory with recursive=false.
   static bool Delete(
       FileSystemOperationContext* context,
       FileSystemFileUtil* file_util,
       const FileSystemURL& url,
       bool recursive,
       const StatusCallback& callback);
 
   // Creates or opens a file with the given flags by calling |file_util|'s
@@ skipping 103 matching lines @@
       int64 length,
       const StatusCallback& callback);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(FileSystemFileUtilProxy);
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_PROXY_H_