Print Preview: Preventing "Preview loading..." animation from rendering when not displayed.

chrome/browser/resources/print_preview_animations.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.
 
 // Counter used to give webkit animations unique names.
 var animationCounter = 0;
 
 function addAnimation(code) {
   var name = 'anim' + animationCounter;
   animationCounter++;
@@ skipping 26 matching lines @@
   }, false );
 }
 
 function fadeOutElement(el) {
   if (!el.classList.contains('visible'))
     return;
   el.style.webkitAnimationName = '';
   el.classList.add('closing');
   el.classList.remove('visible');
 }
+
+function showLoadingAnimation() {
+  $('dancing-dots-text').classList.remove('hidden');
+  $('overlay-layer').classList.remove('invisible');
+}
+
+function hideLoadingAnimation() {
+  var overlayLayer = $('overlay-layer');
+  overlayLayer.addEventListener('webkitTransitionEnd', loadingAnimationCleanup);
+  overlayLayer.classList.add('invisible');
+}
+
+function loadingAnimationCleanup() {
+  $('dancing-dots-text').classList.add('hidden');
+  $('overlay-layer').removeEventListener('webkitTransitionEnd',
+                                         loadingAnimationCleanup);
+}