Cleanup: delete unused local_ntp_util.js

chrome/browser/resources/local_ntp/local_ntp_util.js

-// Copyright 2014 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 Utilities for local_ntp.js.
- */
-
-
-/**
- * A counter with a callback that gets executed on the 1-to-0 transition.
- *
- * @param {function()} callback The callback to be executed.
- * @constructor
- */
-function Barrier(callback) {
-  /** @private {function()} */
-  this.callback_ = callback;
-
-  /** @private {number} */
-  this.count_ = 0;
-
-  /** @private {boolean} */
-  this.isCancelled_ = false;
-}
-
-
-/**
- * Increments count of the Barrier.
- */
-Barrier.prototype.add = function() {
-  ++this.count_;
-};
-
-
-/**
- * Decrements count of the Barrier, and executes callback on 1-to-0 transition.
- */
-Barrier.prototype.remove = function() {
-  if (this.count_ === 0)  // Guards against underflow.
-    return;
-  --this.count_;
-  if (!this.isCancelled_ && this.count_ === 0)
-    this.callback_();
-};
-
-
-/**
- * Deactivates the Barrier; the callback will never be executed.
- */
-Barrier.prototype.cancel = function() {
-  this.isCancelled_ = true;
-};