Issue 5013 - Make parameter const ref when applicable.

src/FileSystemJsObject.cpp

 /*
  * 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 81 matching lines @@
                 const std::string& path, const std::string& content)
       : IoThread(jsEngine, callback), path(path), content(content)
     {
     }
 
     void Run()
     {
       std::string error;
       try
       {
-        std::unique_ptr<std::iostream> stream(new std::stringstream);
-        *stream << content;
-        fileSystem->Write(path, *stream);
+        std::stringstream stream;
+        stream << content;
+        fileSystem->Write(path, stream);
       }
       catch (std::exception& e)
       {
         error = e.what();
       }
       catch (...)
       {
         error = "Unknown error while writing to " + path;
       }
 
@@ skipping 237 matching lines @@
 JsValuePtr FileSystemJsObject::Setup(JsEngine& jsEngine, const JsValuePtr& obj)
 {
   obj->SetProperty("read", jsEngine.NewCallback(::ReadCallback));
   obj->SetProperty("write", jsEngine.NewCallback(::WriteCallback));
   obj->SetProperty("move", jsEngine.NewCallback(::MoveCallback));
   obj->SetProperty("remove", jsEngine.NewCallback(::RemoveCallback));
   obj->SetProperty("stat", jsEngine.NewCallback(::StatCallback));
   obj->SetProperty("resolve", jsEngine.NewCallback(::ResolveCallback));
   return obj;
 }