Issue 3594 - remove circular references JsEngine-JsValue-JsEngine

test/FilterEngine.cpp

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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 515 matching lines @@
   documentUrls1.push_back("http://example.de");
 
   ASSERT_TRUE(filterEngine->IsElemhideWhitelisted(
       "http://example.com",
       documentUrls1));
 
   ASSERT_FALSE(filterEngine->IsElemhideWhitelisted(
       "http://example.co.uk",
       documentUrls1));
 }
+
+TEST(NewFilterEngineTest, MemoryLeak_NoCircularReferences)
+{
+  std::weak_ptr<AdblockPlus::JsEngine> weakJsEngine;
+  {
+    auto jsEngine = AdblockPlus::JsEngine::New();
+    weakJsEngine = jsEngine;
+    jsEngine->SetFileSystem(AdblockPlus::FileSystemPtr(new LazyFileSystem()));
+    jsEngine->SetWebRequest(AdblockPlus::WebRequestPtr(new LazyWebRequest()));
+    jsEngine->SetLogSystem(AdblockPlus::LogSystemPtr(new LazyLogSystem()));
+    auto filterEngine = FilterEnginePtr(new AdblockPlus::FilterEngine(jsEngine));
+  }
+  EXPECT_FALSE(weakJsEngine.lock());
+}