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

chrome/browser/resources/chromeos/switch_access/tree_walker.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.
 
 /**
  * Class to move to the appropriate node in the accessibility tree. Stays in a
  * subtree determined by restrictions passed to it.
  *
  * @constructor
  * @param {!chrome.automation.AutomationNode} start
@@ skipping 23 matching lines @@
    */
   this.leafPred_ = restrictions.leaf;
 
   /**
    * Function that returns true for a node in the current subtree that should
    * be visited.
    *
    * @private {!AutomationTreeWalker.Unary}
    */
   this.visitPred_ = restrictions.visit;
-};
+}
 
 /**
  * @typedef {{leaf: AutomationTreeWalker.Unary,
  *            visit: AutomationTreeWalker.Unary}}
  */
 AutomationTreeWalker.Restriction;
 
 /**
  * @typedef {function(!chrome.automation.AutomationNode) : boolean}
  */
@@ skipping 189 matching lines @@
     let parent = node.parent;
     if (parent) {
       return parent;
     } else {
       console.log('Node has no parent');
       console.log('\n');
       return null;
     }
   }
 };