Issue 4351 - Check History variable exists

safari/include.youtube.js

Index: safari/include.youtube.js
diff --git a/safari/include.youtube.js b/safari/include.youtube.js
index 034d49cf74cbb4d5993bff67b115b975d85f821c..8165fa6dbb5bdbee51484a8373efd87839fe05a7 100644
--- a/safari/include.youtube.js
+++ b/safari/include.youtube.js
@@ -97,7 +97,8 @@
     // 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.