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

chrome/browser/value_store/testing_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/value_store/testing_value_store.h"
 
 #include "base/logging.h"
 
 namespace {
 
@@ skipping 106 matching lines @@
 
 ValueStore::WriteResult TestingValueStore::Clear() {
   std::vector<std::string> keys;
   for (base::DictionaryValue::Iterator it(storage_);
        !it.IsAtEnd(); it.Advance()) {
     keys.push_back(it.key());
   }
   return Remove(keys);
 }
 
+bool TestingValueStore::Restore() {
+  return true;
+}
+
+bool TestingValueStore::RestoreKey(const std::string& key) {
+  return true;
+}
+
 scoped_ptr<ValueStore::Error> TestingValueStore::TestingError() {
   return make_scoped_ptr(new ValueStore::Error(
       error_code_, kGenericErrorMessage, scoped_ptr<std::string>()));
 }