Issue 6652 - Implement fast selector lookups for unknown domains

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 122 matching lines @@
     domain = nextDot == -1 ? null : domain.substring(nextDot + 1);
   }
 
   return filtersList;
 }
 
 /**
  * Returns a list of selectors that apply on a domain from a given list of
  * filters
  * @param {string} [domain]
- * @param {?Array.<?Map.<Filter,boolean>>} filtersList
+ * @param {Array.<?Map.<Filter,boolean>>} filtersList
  * @param {Set.<Filter>} excludeSet
  * @returns {string[]}
  */
 function matchSelectors(domain, filtersList, excludeSet)
 {
   let matches = [];
 
   // This code is a performance hot-spot, which is why we've made certain
   // micro-optimisations. Please be careful before making changes.
   for (let i = 0; i < filtersList.length; i++)
@@ skipping 232 matching lines @@
                getUnconditionalSelectors()
                .concat(getConditionalGenericSelectors());
     }
 
     let excluded = new Set();
     let selectors = matchSelectors(domain, specificFilters, excluded);
 
     if (specificOnly)
       return selectors;
 
-    let genericFilters = [filtersByDomain.get("")];
-    selectors = selectors.concat(matchSelectors(domain, genericFilters,
-                                                excluded));
-    return getUnconditionalSelectors().concat(selectors);
+    return getUnconditionalSelectors()
+           .concat(selectors,
+                   matchSelectors(domain, [filtersByDomain.get("")],
+                                  excluded));
   }
 };