Add a Restore() method to ValueStore and make StorageAPI use it

chrome/browser/extensions/api/storage/policy_value_store.cc

 // 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.
 
 #include "chrome/browser/extensions/api/storage/policy_value_store.h"
 
 #include "base/logging.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/api/storage/settings_namespace.h"
 #include "chrome/browser/value_store/value_store_change.h"
@@ skipping 143 matching lines @@
 
 ValueStore::WriteResult PolicyValueStore::Remove(
     const std::vector<std::string>& keys) {
   return MakeWriteResult(ReadOnlyError(util::NoKey()));
 }
 
 ValueStore::WriteResult PolicyValueStore::Clear() {
   return MakeWriteResult(ReadOnlyError(util::NoKey()));
 }
 
+bool PolicyValueStore::Restore() { return delegate_->Restore(); }
+
+bool PolicyValueStore::RestoreKey(const std::string& key) {
+  return delegate_->RestoreKey(key);
+}
+
 }  // namespace extensions