MD WebUI: Use dom-if to control hidden elements in <cr-toolbar>

chrome/browser/resources/md_downloads/crisper.js

 // Copyright (c) 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.
 function assert(condition, opt_message) {
   if (!condition) {
     var message = 'Assertion failed';
     if (opt_message) message = message + ': ' + opt_message;
     var error = new Error(message);
     var global = function() {
       return this;
@@ skipping 6661 matching lines @@
     narrow: {
       type: Boolean,
       reflectToAttribute: true
     },
     label: String,
     clearLabel: String,
     spinnerActive: {
       type: Boolean,
       reflectToAttribute: true
     },
-    hasSearchText_: Boolean
+    hasSearchText_: Boolean,
+    isSpinnerShown_: {
+      type: Boolean,
+      computed: 'computeIsSpinnerShown_(spinnerActive, showingSearch)'
+    }
   },
   listeners: {
     tap: 'showSearch_',
     'searchInput.bind-value-changed': 'onBindValueChanged_'
   },
   getSearchInput: function() {
     return this.$.searchInput;
   },
   isSearchFocused: function() {
     return this.$.searchTerm.focused;
   },
   computeIconTabIndex_: function(narrow) {
     return narrow ? 0 : -1;
   },
-  isSpinnerShown_: function(spinnerActive, showingSearch) {
-    return spinnerActive && showingSearch;
+  computeIsSpinnerShown_: function() {
+    return this.spinnerActive && this.showingSearch;
   },
   onInputBlur_: function() {
     if (!this.hasSearchText_) this.showingSearch = false;
   },
   onBindValueChanged_: function() {
     var newValue = this.$.searchInput.bindValue;
     this.hasSearchText_ = newValue != '';
     if (newValue != '') this.showingSearch = true;
   },
   showSearch_: function(e) {
@@ skipping 231 matching lines @@
   };
   return {
     Manager: Manager
   };
 });
 
 // Copyright 2015 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.
 window.addEventListener('load', downloads.Manager.onLoad);