Issue 5013 - Make parameter const ref when applicable.

src/Thread.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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef WIN32
 #include <unistd.h>
 #endif
 
 #include "Thread.h"
 
 using namespace AdblockPlus;
 
-void AdblockPlus::Sleep(const int millis)
+void AdblockPlus::Sleep(int millis)
 {
 #ifdef WIN32
   ::Sleep(millis);
 #else
   usleep(millis * 1000);
 #endif
 }
 
 Mutex::Mutex()
 {
@@ skipping 67 matching lines @@
   pthread_join(nativeThread, 0);
 #endif
 }
 
 void Thread::CallRun(Thread* thread)
 {
   thread->Run();
   if (thread->m_deleteSelfOnFinish)
     delete thread;
 }