[Files.app] Split the JavaScript files into subdirectories: common, background, and foreground

chrome/browser/resources/file_manager/foreground/js/ui/search_box.js

 // Copyright 2013 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.
 
 'use strict';
 
 /**
  * Search box.
  *
  * @param {element} element Root element of the search box.
@@ skipping 182 matching lines @@
  * Updates styles of the search box.
  * @private
  */
 SearchBox.prototype.updateStyles_ = function() {
   this.element.classList.toggle('has-text',
                                  !!this.inputElement.value);
   var width = this.textMeasure_.getWidth(this.inputElement.value) +
       16 /* Extra space to allow leeway. */;
   this.inputElement.style.width = width + 'px';
 };