WebUI: Enable ESLint rule for missing semicolons.

chrome/browser/resources/chromeos/login/md_login_shared.js

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview Common OOBE controller methods. This method is shared between
  * OOBE, login, and the lock screen. Add only methods that need to be shared
  * between all *three* screens here, as each additional method increases the
  * time it takes to show the lock screen.
  *
@@ skipping 456 matching lines @@
       // be called then. However, checking it here now causes bots failures
       // unfortunately. So, as a short term workaround, here set
       // readyForTesting even on failures, just to make test bots happy.
       Oobe.readyForTesting = true;
     }
   });
 
   // Install a global error handler so stack traces are included in logs.
   window.onerror = function(message, file, line, column, error) {
     console.error(error.stack);
-  }
+  };
 })();