Issue 6562 - Remove filter keys from the element hiding code

lib/elemHide.js

 /*
  * 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 142 matching lines @@
 
     // Whitelisting filters
     if (filter instanceof ElemHideException)
     {
       let list = exceptions.get(filter.selector);
       let index = list.indexOf(filter);
       if (index >= 0)
         list.splice(index, 1);
     }
     // Unconditially applied element hiding filters
-    else if (filterBySelector.get(filter.selector) === filter)

[Manish Jethani, 2018/05/04 11:59:55]

Looking at the code above, the value returned by filterBySelector.get will
always be a non-null object. In that case we should change the strict equality
here to non-strict equality. There's no harm in keeping it, but when I see a
"===" I think there's a good reason for it to be there, it tells a story, but
here it's just noise.

(It would be the opposite if our style guide mandated "===" and made "==" the
exception.)

[kzar, 2018/05/04 12:06:10]

Done.

+    else if (filterBySelector.get(filter.selector) == filter)
     {
       filterBySelector.delete(filter.selector);
       unconditionalSelectors = null;
     }
     // Conditionally applied element hiding filters
     else
     {
       let domains = filter.domains || defaultDomains;
       for (let domain of domains.keys())
       {
@@ skipping 108 matching lines @@
       if (currentDomain == "")
         break;
 
       let nextDot = currentDomain.indexOf(".");
       currentDomain = nextDot == -1 ? "" : currentDomain.substr(nextDot + 1);
     }
 
     return selectors;
   }
 };