WebUI: Enable ESLint rule for missing semicolons.

chrome/browser/resources/chromeos/chromevox/testing/callback_helper.js

 // Copyright 2015 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.
 
 /**
  * Creates wrappers for callbacks and calls testDone() when all callbacks
  * have been invoked.
  * @param {testing.Test} fixture
  */
 function CallbackHelper(fixture) {
@@ skipping 22 matching lines @@
       if (--this.pendingCallbacks_ <= 0)
         CallbackHelper.testDone_();
     }.bind(this));
     // runAllActionsAsync catches exceptions and puts them in the test
     // framework's list of errors and fails the test if appropriate.
     var runAll = runAllActionsAsync(WhenTestDone.ASSERT, completionAction);
     ++this.pendingCallbacks_;
     return function() {
       savedArgs.arguments = Array.prototype.slice.call(arguments);
       runAll.invoke();
-    }
+    };
   }
 };
 
 /**
  * @private
  */
 CallbackHelper.testDone_ = this.testDone;
 // Remove testDone for public use since direclty using it conflicts with
 // this callback helper.
 delete this.testDone;