Add a method to check whether ABP is fully initialised

src/FilterEngine.cpp

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2013 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 120 matching lines @@
 {
   return GetProperty("url")->AsString() == subscription.GetProperty("url")->AsString();
 }
 
 FilterEngine::FilterEngine(JsEnginePtr jsEngine) : jsEngine(jsEngine)
 {
   for (int i = 0; !jsSources[i].empty(); i += 2)
     jsEngine->Evaluate(jsSources[i + 1], jsSources[i]);
 }
 
+bool FilterEngine::IsInitialized() const
+{
+  return jsEngine->Evaluate("_abpInitialized")->AsBool();
+}
+
 FilterPtr FilterEngine::GetFilter(const std::string& text)
 {
   JsValuePtr func = jsEngine->Evaluate("API.getFilterFromText");
   JsValueList params;
   params.push_back(jsEngine->NewValue(text));
   return FilterPtr(new Filter(func->Call(params)));
 }
 
 SubscriptionPtr FilterEngine::GetSubscription(const std::string& url)
 {
@@ skipping 53 matching lines @@
 {
   JsValuePtr func = jsEngine->Evaluate("API.getElementHidingSelectors");
   JsValueList params;
   params.push_back(jsEngine->NewValue(domain));
   JsValueList result = func->Call(params)->AsList();
   std::vector<std::string> selectors;
   for (JsValueList::iterator it = result.begin(); it != result.end(); ++it)
     selectors.push_back((*it)->AsString());
   return selectors;
 }