Convert references to FileSystem & Co. into shared pointers (avoid use after free)

src/WebRequestJsObject.cpp

 #include <map>
 #include <AdblockPlus/JsEngine.h>
 #include <AdblockPlus/JsValue.h>
 #include <AdblockPlus/WebRequest.h>
 #include "WebRequestJsObject.h"
 #include "Thread.h"
 
 namespace
 {
   class WebRequestThread : public AdblockPlus::Thread
@@ skipping 21 matching lines @@
         }
       }
 
       callback = arguments[2];
       if (!callback->IsFunction())
         throw std::runtime_error("Third argument to GET must be a function");
     }
 
     void Run()
     {
-      AdblockPlus::ServerResponse result = jsEngine.GetWebRequest().GET(url, headers);
+      AdblockPlus::ServerResponse result = jsEngine.GetWebRequest()->GET(url, headers);
 
       AdblockPlus::JsEngine::Context context(jsEngine);
 
       AdblockPlus::JsValuePtr resultObject = jsEngine.NewObject();
       resultObject->SetProperty("status", result.status);
       resultObject->SetProperty("responseStatus", result.responseStatus);
       resultObject->SetProperty("responseText", result.responseText);
 
       AdblockPlus::JsValuePtr headersObject = jsEngine.NewObject();
       for (AdblockPlus::HeaderList::iterator it = result.responseHeaders.begin();
@@ skipping 35 matching lines @@
     return v8::Undefined();
   }
 }
 
 AdblockPlus::JsValuePtr AdblockPlus::WebRequestJsObject::Setup(
     AdblockPlus::JsEngine& jsEngine, AdblockPlus::JsValuePtr obj)
 {
   obj->SetProperty("GET", jsEngine.NewCallback(::GETCallback));
   return obj;
 }