Bug 31126: Use URLSearchParams instead of Query.parse.

This standard interface does the same thing as Query.parse did, with a
different API on the return value. It doesn't have the problems with
keys inherited from Object.prototype that Query.parse did.

proxy/shims.js

@@ -13,6 +13,7 @@ if (typeof module !== "undefined" && module !== null ? module.exports : void 0)
   };
   chrome = {};
   location = { search: '' };
+  ({ URLSearchParams } = require('url'));
   if ((typeof TESTING === "undefined" || TESTING === null) || !TESTING) {
     webrtc = require('wrtc');
     PeerConnection = webrtc.RTCPeerConnection;