Issue 5183 - Provide async interface for FileSystem

test/FilterEngine.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 106 matching lines @@
               if (error.empty() && stats.exists)
               {
                 fs->Remove(path, [&sync](const std::string& error)
                   {
                     sync.Set(error);
                   });
               }
               else
                 sync.Set(error);
             });
-          sync.Wait();
+          sync.WaitFor();
           return sync.GetError().empty();
         }
         catch (...)
         {
           return false;
         }
       };
       int i = 5;
       while ((i-- > 0 && weakJsEngine.lock()) || !safeRemove())
         std::this_thread::sleep_for(std::chrono::seconds(2));
@@ skipping 887 matching lines @@
     std::string testConnection = "test connection";
     filterEngine->SetAllowedConnectionType(&testConnection);
     auto subscription = EnsureExampleSubscriptionAndForceUpdate("subB");
     EXPECT_EQ("synchronize_ok", subscription.GetProperty("downloadStatus").AsString());
     EXPECT_EQ(1u, subscription.GetProperty("filters").AsList().size());
     ASSERT_EQ(1u, capturedConnectionTypes.size());
     EXPECT_TRUE(capturedConnectionTypes[0].first);
     EXPECT_EQ(testConnection, capturedConnectionTypes[0].second);
   }
 }