Print Preview Cleanup: Creating enum with all custom events used.

chrome/browser/resources/print_preview/preview_area.js

 // Copyright (c) 2011 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.
 
 cr.define('print_preview', function() {
   'strict';
 
   /**
    * Creates a PreviewArea object. It represents the area where the preview
    * document is displayed.
@@ skipping 116 matching lines @@
         };
       }
       this.pdfLoaded_ = false;
     },
 
     /**
      * Adds event listeners for various events.
      * @private
      */
     addEventListeners_: function() {
-      document.addEventListener('PDFLoaded',
+      document.addEventListener(customEvents.PDF_LOADED,
                                 this.onPDFLoaded_.bind(this));
     },
 
     /**
-     * Listener executing when a PDFLoaded event occurs.
+     * Listener executing when a |customEvents.PDF_LOADED| event occurs.
      * @private
      */
     onPDFLoaded_: function() {
       this.pdfPlugin_ = $('pdf-viewer');
       this.pdfLoaded_ = true;
       if (this.zoomLevel_ != null && this.pageOffset_ != null) {
         this.pdfPlugin_.setZoomLevel(this.zoomLevel_);
         this.pdfPlugin_.setPageXOffset(this.pageOffset_.x);
         this.pdfPlugin_.setPageYOffset(this.pageOffset_.y);
       } else {
@@ skipping 48 matching lines @@
     displayErrorMessageAndNotify: function(errorMessage) {
       this.overlayLayer.classList.remove('invisible');
       this.customMessage_.textContent = errorMessage;
       this.customMessage_.hidden = false;
       this.customMessageWithDots_.innerHTML = '';
       this.customMessageWithDots_.hidden = true;
       if (this.pdfPlugin_) {
         $('mainview').removeChild(this.pdfPlugin_);
         this.pdfPlugin_ = null;
       }
-      cr.dispatchSimpleEvent(document, 'PDFGenerationError');
+      cr.dispatchSimpleEvent(document, customEvents.PDF_GENERATION_ERROR);
     },
 
     /**
      * Display an error message in the center of the preview area followed by a
      * button.
      * @param {string} errorMessage The error message to be displayed.
      * @param {string} buttonText The text to be displayed within the button.
      * @param {string} buttonListener The listener to be executed when the
      *     button is clicked.
      */
     displayErrorMessageWithButtonAndNotify: function(
         errorMessage, buttonText, buttonListener) {
       this.errorButton.disabled = false;
       this.errorButton.textContent = buttonText;
       this.errorButton.onclick = buttonListener;
       this.errorButton.hidden = false;
       $('system-dialog-throbber').hidden = true;
       $('native-print-dialog-throbber').hidden = true;
       this.displayErrorMessageAndNotify(errorMessage);
     }
   };
 
   return {
     PreviewArea: PreviewArea,
   };
 });