Issue 5450 - don't expose std::shared_ptr<JsEngine>

test/BaseJsTest.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 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 249 matching lines @@
 struct ThrowingPlatformCreationParameters: AdblockPlus::Platform::CreationParameters
 {
   ThrowingPlatformCreationParameters();
 };
 
 class BaseJsTest : public ::testing::Test
 {
 protected:
   std::unique_ptr<AdblockPlus::Platform> platform;
 
-  virtual void SetUp()
+  void SetUp() override
   {
     platform.reset(new AdblockPlus::Platform(ThrowingPlatformCreationParameters()));
   }
+
+  AdblockPlus::JsEngine& GetJsEngine()
+  {
+    if (!platform)
+      throw std::runtime_error("Platform must be initialized");
+    return platform->GetJsEngine();
+  }
+
+  void TearDown() override
+  {
+    if (platform)
+      platform.reset();
+  }
 };
 
 #endif