Make Print Preview elements transitions smoother.

chrome/browser/resources/print_preview/settings/settings_section.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.
 
 cr.define('print_preview', function() {
   'use strict';
 
   /**
    * Base class for print option section components.
    * @constructor
    * @extends {print_preview.Component}
    */
   function SettingsSection() {
     print_preview.Component.call(this);
 
     /**
      * Cached "hasCollapsibleContent" status for COLLAPSIBLE_CONTENT_CHANGED
      * notification.
      * @private {?boolean}
      */
     this.hasCollapsibleContentCached_ = null;
 
     /**
      * Whether content of this section should be collapsed or not.
      * @private {boolean}
      */
-    this.collapseContent_ = false;
+    this.collapseContent_ = true;
   };
 
   /**
    * Event types dispatched by this class.
    * @enum {string}
    */
   SettingsSection.EventType = {
     COLLAPSIBLE_CONTENT_CHANGED:
         'print_preview.SettingsSection.COLLAPSIBLE_CONTENT_CHANGED'
   };
@@ skipping 23 matching lines @@
      * @return {boolean} Whether the content of this section should be
      *     collapsed.
      */
     get collapseContent() {
       return this.collapseContent_;
     },
 
     /**
      * @param {boolean} collapseContent Whether the content of this section
      *     should be collapsed, even if this section is available.
+     * @param {boolean} noAnimation Whether section visibility transition
+     *     should not be animated.
      */
-    set collapseContent(collapseContent) {
+    setCollapseContent: function(collapseContent, noAnimation) {
       this.collapseContent_ = collapseContent && this.hasCollapsibleContent();
-      this.updateUiStateInternal();
+      this.updateUiStateInternal(noAnimation);
     },
 
     /** @override */
     enterDocument: function() {
       print_preview.Component.prototype.enterDocument.call(this);
       this.isAvailable_ = this.isAvailable();
       if (!this.isAvailable())
         fadeOutOption(this.getElement(), true);
     },
 
     /**
      * Updates the component appearance according to the current state.
+     * @param {boolean=} opt_noAnimation Whether section visibility transition
+     *     should not be animated.
      * @protected
      */
-    updateUiStateInternal: function() {
+    updateUiStateInternal: function(opt_noAnimation) {
       var hasCollapsibleContent = this.hasCollapsibleContent();
       var changed = this.hasCollapsibleContentCached_ != hasCollapsibleContent;
       this.hasCollapsibleContentCached_ = hasCollapsibleContent;
 
       if (this.isSectionVisibleInternal())
-        fadeInOption(this.getElement());
+        fadeInOption(this.getElement(), opt_noAnimation);
       else
-        fadeOutOption(this.getElement());
+        fadeOutOption(this.getElement(), opt_noAnimation);
 
       if (changed) {
         cr.dispatchSimpleEvent(
             this, SettingsSection.EventType.COLLAPSIBLE_CONTENT_CHANGED);
       }
     },
 
     /**
      * @return {boolean} Whether this section should be displayed or not.
      * @protected
      */
     isSectionVisibleInternal: function() {
       return this.isAvailable() && !this.collapseContent_;
     }
   };
 
   // Export
   return {
     SettingsSection: SettingsSection
   };
 });