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

chrome/browser/extensions/api/storage/settings_test_util.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_EXTENSIONS_API_STORAGE_SETTINGS_TEST_UTIL_H_
 #define CHROME_BROWSER_EXTENSIONS_API_STORAGE_SETTINGS_TEST_UTIL_H_
 
 #include <set>
 #include <string>
 
@@ skipping 84 matching lines @@
 
   explicit ScopedSettingsStorageFactory(
       const scoped_refptr<SettingsStorageFactory>& delegate);
 
   // Sets the delegate factory (equivalent to scoped_ptr::reset).
   void Reset(const scoped_refptr<SettingsStorageFactory>& delegate);
 
   // SettingsStorageFactory implementation.
   virtual ValueStore* Create(const base::FilePath& base_path,
                              const std::string& extension_id) OVERRIDE;
+  virtual void DeleteDatabaseIfExists(
+      const base::FilePath& base_path,
+      const std::string& extension_id) OVERRIDE;
 
  private:
   // SettingsStorageFactory is refcounted.
   virtual ~ScopedSettingsStorageFactory();
 
   scoped_refptr<SettingsStorageFactory> delegate_;
 };
 
 }  // namespace settings_test_util
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_STORAGE_SETTINGS_TEST_UTIL_H_