Implement an initial extension settings API.

chrome/browser/extensions/extension_settings_noop_storage.h

+// Copyright (c) 2011 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_EXTENSION_SETTINGS_NOOP_STORAGE_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTENSION_SETTINGS_NOOP_STORAGE_H_
+#pragma once
+
+#include "chrome/browser/extensions/extension_settings_storage.h"
+
+// Implementation of ExtensionSettingsStorage which does nothing, but behaves
+// as though each Get/Set were successful.
+// Intended to be wrapped by a Cache for trivial in-memory storage.
+class ExtensionSettingsNoopStorage : public ExtensionSettingsStorage {
+ public:
+  ExtensionSettingsNoopStorage() {}
+  ~ExtensionSettingsNoopStorage() {}
+
+  int type() { return NOOP; }
+
+  void Get(const std::string& key, Callback* callback);
+  void Get(const ListValue& keys, Callback* callback);
+  void Get(Callback* callback);
+  void Set(const std::string& key, const Value& value, Callback* callback);
+  void Set(const DictionaryValue& values, Callback* callback);
+  void Remove(const std::string& key, Callback* callback);
+  void Remove(const ListValue& keys, Callback* callback);
+  void Clear(Callback *callback);
+};
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SETTINGS_NOOP_STORAGE_H_