Migrate WebUSB LayoutTests into external/wpt

third_party/WebKit/LayoutTests/external/wpt/resources/chromium/webusb-test.js

 'use strict';
 
 // This polyfill library implements the WebUSB Test API as specified here:
 // https://wicg.github.io/webusb/test/
 
 (() => {
 
 // These variables are logically members of the USBTest class but are defined
 // here to hide them from being visible as fields of navigator.usb.test.
 let internal = {
@@ skipping 499 matching lines @@
         internal.chooser.setChosenDevice(null);
         resolve();
       }, 0);
     });
   }
 }
 
 navigator.usb.test = new USBTest();
 
 })();