Template out V8 and prepare for other JS engine implementations

src/WebRequestJsObject.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef ADBLOCK_PLUS_WEB_REQUEST_JS_OBJECT_H
 #define ADBLOCK_PLUS_WEB_REQUEST_JS_OBJECT_H
 
 #include <AdblockPlus/JsEngine.h>
 
 namespace AdblockPlus
 {
-  class JsEngine;
+  template <class T> class JsEngineTemplate;
+#ifndef JSENGINEIMPL
+#define JSENGINEIMPL JsEngineTemplate<JsEngineNamespaceImpl>
+#endif
+  typedef JSENGINEIMPL JsEngine;
+
+  template <class T> class JsValueTemplate;
+#ifndef JSVALUEIMPL
+#define JSVALUEIMPL JsValueTemplate<JsEngineNamespaceImpl>
+#endif
+  typedef JSVALUEIMPL JsValue;
 
   namespace WebRequestJsObject
   {
     JsValue& Setup(JsEngine& jsEngine, JsValue& obj);
   }
 }
 
 #endif