Refactor the DB code to make all DB layout tests pass on test_shell....

webkit/database/vfs_backend.h

Index: webkit/database/vfs_backend.h
===================================================================
--- webkit/database/vfs_backend.h	(revision 0)
+++ webkit/database/vfs_backend.h	(revision 0)
@@ -0,0 +1,33 @@
+// Copyright (c) 2009 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_DATABASE_VFS_BACKEND_H_
+#define WEBKIT_DATABASE_VFS_BACKEND_H_
+
+#include "base/platform_file.h"
+#include "base/process.h"
+
+class FilePath;
+
+namespace webkit_database {
+
+class VfsBackend {
+ public:
+  static void OpenFile(
+      const FilePath& file_name, const FilePath& db_dir, int desired_flags,
+      base::ProcessHandle handle, base::PlatformFile* target_handle,
+      base::PlatformFile* target_dir_handle);
+  static int DeleteFile(
+      const FilePath& file_name, const FilePath& db_dir, bool sync_dir);
+  static uint32 GetFileAttributes(const FilePath& file_name);
+  static int64 GetFileSize(const FilePath& file_name);
+
+ private:
+  static bool OpenFileFlagsAreConsistent(
+      const FilePath& file_name, const FilePath& db_dir, int desired_flags);
+};
+
+}  // namespace webkit_database
+
+#endif  // WEBKIT_DATABASE_VFS_BACKEND_H_