Issue 5094 - Implement support for :has() in chrome extension

lib/filterValidation.js

Index: lib/filterValidation.js
===================================================================
--- a/lib/filterValidation.js
+++ b/lib/filterValidation.js
@@ -14,17 +14,18 @@
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 /** @module filterValidation */
 
 "use strict";
 
-const {Filter, InvalidFilter, ElemHideBase} = require("filterClasses");
+const {Filter, InvalidFilter, ElemHideBase, ElemHideEmulationFilter} =
+      require("filterClasses");
 const {Utils} = require("utils");
 
 /**
  * An error returned by
  * {@link module:filterValidation.parseFilter parseFilter()} or
  * {@link module:filterValidation.parseFilters parseFilters()}
  * indicating that a given filter cannot be parsed,
  * contains an invalid CSS selector or is a filter list header.
@@ -137,17 +138,19 @@
 
     filter = Filter.fromText(text);
 
     if (filter instanceof InvalidFilter)
     {
       return {error: new FilterParsingError("invalid-filter",
                                             {reason: filter.reason})};
     }
-    if (filter instanceof ElemHideBase && !isValidCSSSelector(filter.selector))
+    if (filter instanceof ElemHideBase &&
+        !(filter instanceof ElemHideEmulationFilter) &&
+        !isValidCSSSelector(filter.selector))
     {
       return {error: new FilterParsingError("invalid-css-selector",
                                             {selector: filter.selector})};
     }
   }
 
   return {filter};
 };