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

chrome/browser/extensions/api/storage/settings_sync_unittest.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 "base/bind.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 158 matching lines @@
 
   // SettingsStorageFactory implementation.
   virtual ValueStore* Create(const base::FilePath& base_path,
                              const std::string& extension_id) OVERRIDE {
     TestingValueStore* new_storage = new TestingValueStore();
     DCHECK(!created_.count(extension_id));
     created_[extension_id] = new_storage;
     return new_storage;
   }
 
+  // Testing value stores don't actually create a real database. Don't delete
+  // any files.
+  virtual void DeleteDatabaseIfExists(
+      const base::FilePath& base_path,
+      const std::string& extension_id) OVERRIDE {}
+
  private:
   // SettingsStorageFactory is refcounted.
   virtual ~TestingValueStoreFactory() {}
 
   // None of these storage areas are owned by this factory, so care must be
   // taken when calling GetExisting.
   std::map<std::string, TestingValueStore*> created_;
 };
 
 }  // namespace
@@ skipping 1222 matching lines @@
     ASSERT_EQ(1u, sync_processor_->changes().size());
     SettingSyncData sync_data = sync_processor_->changes()[0];
     EXPECT_EQ(syncer::SyncChange::ACTION_ADD, sync_data.change_type());
     EXPECT_EQ("ext", sync_data.extension_id());
     EXPECT_EQ("key.with.spot", sync_data.key());
     EXPECT_TRUE(sync_data.value().Equals(string_value.get()));
   }
 }
 
 }  // namespace extensions