Print Preview: Make getChildElement return required HTMLElement

chrome/browser/resources/print_preview/settings/advanced_settings/advanced_settings.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';
 
   /**
    * Modal dialog for print destination's advanced settings.
    * @param {!print_preview.PrintTicketStore} printTicketStore Contains the
@@ skipping 52 matching lines @@
                                   this.destination_.displayName);
       this.setIsVisible(true);
       this.renderSettings_();
     },
 
     /** @override */
     enterDocument: function() {
       print_preview.Overlay.prototype.enterDocument.call(this);
 
       this.tracker.add(
-          assert(this.getChildElement('.button-strip .cancel-button')),
+          this.getChildElement('.button-strip .cancel-button'),
           'click',
           this.cancel.bind(this));
 
       this.tracker.add(
-          assert(this.getChildElement('.button-strip .done-button')),
+          this.getChildElement('.button-strip .done-button'),
           'click',
           this.onApplySettings_.bind(this));
 
       this.tracker.add(
           assert(this.searchBox_),
           print_preview.SearchBox.EventType.SEARCH,
           this.onSearch_.bind(this));
     },
 
     /** @override */
     decorateInternal: function() {
-      this.searchBox_.render(assert(this.getChildElement('.search-box-area')));
+      this.searchBox_.render(this.getChildElement('.search-box-area'));
     },
 
     /** @override */
     onSetVisibleInternal: function(isVisible) {
       if (isVisible) {
         this.searchBox_.focus();
         this.metrics_.record(print_preview.Metrics.PrintSettingsUiBucket.
             ADVANCED_SETTINGS_DIALOG_SHOWN);
       } else {
         this.resetSearch_();
@@ skipping 37 matching lines @@
       var atLeastOneMatch = false;
       var lastVisibleItemWithBubble = null;
       this.items_.forEach(function(item) {
         item.updateSearchQuery(query);
         if (getIsVisible(item.getElement()))
           atLeastOneMatch = true;
         if (item.searchBubbleShown)
           lastVisibleItemWithBubble = item;
       });
       setIsVisible(
-          assert(this.getChildElement('.no-settings-match-hint')),
+          this.getChildElement('.no-settings-match-hint'),
           !atLeastOneMatch);
       setIsVisible(
-          assert(this.getChildElement(
-              '.' + AdvancedSettings.Classes_.EXTRA_PADDING)),
+          this.getChildElement('.' + AdvancedSettings.Classes_.EXTRA_PADDING),
           !!lastVisibleItemWithBubble);
     },
 
     /**
      * Resets the filter query.
      * @private
      */
     resetSearch_: function() {
       this.searchBox_.setQuery(null);
       this.filterLists_(null);
     },
 
     /**
      * Renders all of the available settings.
      * @private
      */
     renderSettings_: function() {
       // Remove all children settings elements.
       this.items_.forEach(function(item) {
         this.removeChild(item);
       }.bind(this));
       this.items_ = [];
 
-      var extraPadding =
-          this.getChildElement('.' + AdvancedSettings.Classes_.EXTRA_PADDING);
+      var extraPadding = this.element_.querySelector(
+          '.' + AdvancedSettings.Classes_.EXTRA_PADDING);
       if (extraPadding)
         extraPadding.parentNode.removeChild(extraPadding);
 
       var vendorCapabilities = this.printTicketStore_.vendorItems.capability;
       if (!vendorCapabilities)
         return;
 
       var availableHeight = this.getAvailableContentHeight_();
       var containerEl = this.getChildElement('.settings-area');
       containerEl.style.maxHeight = availableHeight + 'px';
       var settingsEl = this.getChildElement('.settings');
 
       vendorCapabilities.forEach(function(capability) {
         var item = new print_preview.AdvancedSettingsItem(
             this.printTicketStore_, capability);
         this.addChild(item);
-        item.render(assert(settingsEl));
+        item.render(settingsEl);
         this.items_.push(item);
       }.bind(this));
 
-      var searchBoxArea = assert(this.getChildElement('.search-box-area'));
+      var searchBoxArea = this.getChildElement('.search-box-area');
       if (this.items_.length <= 1) {
         setIsVisible(searchBoxArea, false);
       } else {
         setIsVisible(searchBoxArea, true);
         this.searchBox_.focus();
       }
 
       extraPadding = document.createElement('div');
       extraPadding.classList.add(AdvancedSettings.Classes_.EXTRA_PADDING);
       extraPadding.hidden = true;
@@ skipping 25 matching lines @@
 
       this.printTicketStore_.vendorItems.updateValue(values);
     }
   };
 
   // Export
   return {
     AdvancedSettings: AdvancedSettings
   };
 });