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

chrome/browser/value_store/testing_value_store.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 CHROME_BROWSER_VALUE_STORE_TESTING_VALUE_STORE_H_
 #define CHROME_BROWSER_VALUE_STORE_TESTING_VALUE_STORE_H_
 
 #include "base/compiler_specific.h"
 #include "chrome/browser/value_store/value_store.h"
 
@@ skipping 25 matching lines @@
   virtual ReadResult Get() OVERRIDE;
   virtual WriteResult Set(
       WriteOptions options,
       const std::string& key,
       const base::Value& value) OVERRIDE;
   virtual WriteResult Set(
       WriteOptions options, const base::DictionaryValue& values) OVERRIDE;
   virtual WriteResult Remove(const std::string& key) OVERRIDE;
   virtual WriteResult Remove(const std::vector<std::string>& keys) OVERRIDE;
   virtual WriteResult Clear() OVERRIDE;
+  virtual bool Restore() OVERRIDE;
+  virtual bool RestoreKey(const std::string& key) OVERRIDE;
 
  private:
   scoped_ptr<ValueStore::Error> TestingError();
 
   base::DictionaryValue storage_;
   int read_count_;
   int write_count_;
   ErrorCode error_code_;
 
   DISALLOW_COPY_AND_ASSIGN(TestingValueStore);
 };
 
 #endif  // CHROME_BROWSER_VALUE_STORE_TESTING_VALUE_STORE_H_