Move the shadow-dom directory from web-platform-tests/ to wpt/.

third_party/WebKit/LayoutTests/imported/wpt/resources/vendor-prefix.js

 /*
  * Distributed under both the W3C Test Suite License [1] and the W3C
  * 3-clause BSD License [2]. To contribute to a W3C Test Suite, see the
  * policies and contribution forms [3].
  *
  * [1] http://www.w3.org/Consortium/Legal/2008/04-testsuite-license
  * [2] http://www.w3.org/Consortium/Legal/2008/03-bsd-license
  * [3] http://www.w3.org/2004/10/27-testcases
  * */
 
@@ skipping 80 matching lines @@
     if (document.querySelector("script[data-prefixed-prototypes]")) {
         var prefixProtoData = document.querySelector("script[data-prefixed-prototypes]").dataset["prefixedPrototypes"];
         try {
             var prefixedPrototypes = JSON.parse(prefixProtoData);
         } catch (e) {
             throw "couldn't parse data-prefixed-prototypes as JSON:" + e;
         }
         prefixedPrototypes.forEach(setPrototypeAlias);
     }
 })();