Issue 6299 - Avoid main thread lock on URL loading

libadblockplus-android/src/org/adblockplus/libadblockplus/android/SingleInstanceEngineProvider.java

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present 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 171 matching lines @@
   @Override
   public void waitForReady()
   {
     if (engineCreated == null)
     {
       throw new IllegalStateException("Usage exception: call retain(true) first");
     }
 
     try
     {
-      Log.d(TAG, "Waiting for ready ...");
+      Log.d(TAG, "Waiting for ready in " + Thread.currentThread());
       engineCreated.await();
       Log.d(TAG, "Ready");
     }
     catch (InterruptedException e)
     {
       Log.w(TAG, "Interrupted", e);
     }
   }
 
   @Override
@@ skipping 43 matching lines @@
       engineDisposedCallback.run();
     }
   }
 
   @Override
   public int getCounter()
   {
     return referenceCounter.get();
   }
 }