mash: Add a simple, temporary preferences store.

components/filesystem/public/cpp/prefs/pref_service_factory.h

Index: components/filesystem/public/cpp/prefs/pref_service_factory.h
diff --git a/components/filesystem/public/cpp/prefs/pref_service_factory.h b/components/filesystem/public/cpp/prefs/pref_service_factory.h
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index 0000000000000000000000000000000000000000..ccf981e27c2b0ce30deb048446ec2aea330413bb
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+++ b/components/filesystem/public/cpp/prefs/pref_service_factory.h
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+// Copyright 2016 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 COMPONENTS_FILESYSTEM_PUBLIC_CPP_PREFS_PREF_SERVICE_FACTORY_H_
+#define COMPONENTS_FILESYSTEM_PUBLIC_CPP_PREFS_PREF_SERVICE_FACTORY_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "base/prefs/pref_service.h"
+
+namespace mojo {
+class ApplicationImpl;
+}
+
+class PrefRegistry;
+
+namespace filesystem {
+
+// This factory method creates a PrefService for the local process based on the
+// preference registry passed in. This PrefService will synchronize with a JSON
+// file in the mojo:filesystem.
+scoped_ptr<PrefService> CreatePrefService(mojo::ApplicationImpl* application,
+                                          PrefRegistry* registry);
+
+}  // namespace filesystem
+
+#endif  // COMPONENTS_FILESYSTEM_PUBLIC_CPP_PREFS_PREF_SERVICE_FACTORY_H_