[Extensions Bindings] Add ChromeSetting custom type

extensions/renderer/storage_area.h

 // Copyright 2017 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 EXTENSIONS_RENDERER_STORAGE_AREA_H_
 #define EXTENSIONS_RENDERER_STORAGE_AREA_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/strings/string_piece.h"
 #include "v8/include/v8.h"
 
 namespace gin {
 class Arguments;
 }
 
 namespace extensions {
+class APIEventHandler;
 class APIRequestHandler;
 class APITypeReferenceMap;
 
 // Implementation of the storage.StorageArea custom type used in the
 // chrome.storage API.
 class StorageArea {
  public:
   StorageArea(APIRequestHandler* request_handler,
               const APITypeReferenceMap* type_refs,
               const std::string& name);
   ~StorageArea();
 
   // Creates a StorageArea object for the given context and property name.
   static v8::Local<v8::Object> CreateStorageArea(
       v8::Local<v8::Context> context,
       const std::string& property_name,
       APIRequestHandler* request_handler,
+      APIEventHandler* event_handler,
       APITypeReferenceMap* type_refs);
 
   void HandleFunctionCall(const std::string& method_name,
                           gin::Arguments* arguments);
 
  private:
   APIRequestHandler* request_handler_;
 
   const APITypeReferenceMap* type_refs_;
 
   std::string name_;
 
   DISALLOW_COPY_AND_ASSIGN(StorageArea);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_STORAGE_AREA_H_