Issue 4351 - Check History variable exists

safari/include.youtube.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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 79 matching lines @@
 
   runInPageContext(function(badArgumentsRegexSource)
   {
     var badArgumentsRegex = new RegExp(badArgumentsRegexSource);
 
     // If history.pushState is available, YouTube uses the history API
     // when navigation from one video to another, and tells the flash
     // player with JavaScript which video and which ads to show next,
     // bypassing our flashvars rewrite code. So we disable
     // history.pushState before YouTube's JavaScript runs.
-    History.prototype.pushState = undefined;
+    if (typeof History != "undefined")

[Sebastian Noack, 2016/10/12 15:51:58]

It seems that the History object is supported since Safari 5:
https://developer.mozilla.org/en-US/docs/Web/API/History

I suggest to first reproduce this issue, before taking any premature actions.

[Sebastian Noack, 2016/10/12 18:03:35]

Fair enough, lets give it a try. But please check with Robert, whether this
actually fixes blocking of YouTube ads, and revert this change if it does not.

While it should avoid that exception, it is still unclear why the History object
isn't there in the first place. There might be a larger issue, which causes more
problems down the code path. Or the History object might just not be visible to
our script for some reason, but to YouTube's script in which case ads will be
back when clicking on another video.

+      History.prototype.pushState = undefined;
 
     // The HTML5 player is configured via ytplayer.config.args. We have
     // to make sure that ad-related arguments are ignored as they are set.
     var ytplayer = undefined;
     Object.defineProperty(window, "ytplayer",
     {
       configurable: true,
       get: function()
       {
         return ytplayer;
@@ skipping 51 matching lines @@
               config.args = rawConfig.args;
             }
           }
         });
 
         ytplayer.config = rawYtplayer.config;
       }
     });
   }, badArgumentsRegex.source);
 })();