WebUI: Fix violations of no-extra-semi lint rule.

chrome/browser/resources/chromeos/switch_access/keyboard_handler.js

 // Copyright 2017 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.
 
 // TODO(elichtenberg): Move into custom logger class or somewhere else.
 let debuggingEnabled = true;
 
 /**
  * Class to handle keyboard input.
  *
  * @constructor
  * @param {SwitchAccessInterface} switchAccess
  */
 function KeyboardHandler(switchAccess) {
   /**
    * SwitchAccess reference.
    * @private {SwitchAccessInterface}
    */
   this.switchAccess_ = switchAccess;
 
   this.init_();
-};
+}
 
 KeyboardHandler.prototype = {
   /**
    * Set up key listener.
    *
    * @private
    */
   init_: function() {
     document.addEventListener('keyup', this.handleKeyEvent_.bind(this));
   },
@@ skipping 38 matching lines @@
           break;
         case '9':
           console.log('9 = go to parent element (debug mode)');
           this.switchAccess_.debugMoveToParent();
           break;
       }
     }
     this.switchAccess_.performedUserAction();
   }
 };