Issue #3593, #1197- fix isolate management

src/JsEngine.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 47 matching lines @@
     static void Init()
     {
       // it's threadsafe since C++11 and it will be instantiated only once and
       // destroyed at the application exit
       static V8Initializer initializer;
     }
   };
 }
 
 AdblockPlus::ScopedV8Isolate::ScopedV8Isolate()
-  : isolate(v8::Isolate::New())
-{
+{
+  V8Initializer::Init();
+  isolate = v8::Isolate::New();
 }
 
 AdblockPlus::ScopedV8Isolate::~ScopedV8Isolate()
 {
   isolate->Dispose();
   isolate = nullptr;
 }
 
 AdblockPlus::JsEngine::JsEngine(const ScopedV8IsolatePtr& isolate)
   : isolate(isolate)
 {
 }
 
 AdblockPlus::JsEnginePtr AdblockPlus::JsEngine::New(const AppInfo& appInfo, const ScopedV8IsolatePtr& isolate)
 {
-  V8Initializer::Init();
   JsEnginePtr result(new JsEngine(isolate));
 
   const v8::Locker locker(result->GetIsolate());
   const v8::Isolate::Scope isolateScope(result->GetIsolate());
   const v8::HandleScope handleScope(result->GetIsolate());
 
   result->context.reset(new v8::Persistent<v8::Context>(result->GetIsolate(),
     v8::Context::New(result->GetIsolate())));
   v8::Local<v8::Object> globalContext = v8::Local<v8::Context>::New(
     result->GetIsolate(), *result->context)->Global();
@@ skipping 146 matching lines @@
 
 
 void AdblockPlus::JsEngine::SetGlobalProperty(const std::string& name, 
                                               AdblockPlus::JsValuePtr value)
 {
   if (!globalJsObject)
     throw std::runtime_error("Global object cannot be null");
 
   globalJsObject->SetProperty(name, value);
 }