Template out V8 and prepare for other JS engine implementations

src/Platform.cpp

 /*
 * 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
@@ skipping 44 matching lines @@
 }
 
 void Platform::SetUpJsEngine(const AppInfo& appInfo, std::unique_ptr<IV8IsolateProvider> isolate)
 {
   std::lock_guard<std::mutex> lock(modulesMutex);
   if (jsEngine)
     return;
   jsEngine = JsEngine::New(appInfo, *this, std::move(isolate));
 }
 
-JsEngine& Platform::GetJsEngine()
+JsEngineTemplate<JsEngineNamespaceImpl>& Platform::GetJsEngine()
 {
   SetUpJsEngine();
   return *jsEngine;
 }
 
 void Platform::CreateFilterEngineAsync(const FilterEngine::CreationParameters& parameters,
   const OnFilterEngineCreatedCallback& onCreated)
 {
   std::shared_ptr<std::promise<FilterEnginePtr>> filterEnginePromise;
   {
@@ skipping 153 matching lines @@
     CreateDefaultTimer();
   if (!fileSystem)
     CreateDefaultFileSystem();
   if (!webRequest)
     CreateDefaultWebRequest();
 
   std::unique_ptr<Platform> platform(new DefaultPlatform(asyncExecutor, std::move(*this)));
   asyncExecutor.reset();
   return platform;
 }