Replace aria-active-attribute in WebUI

With the switch to cr-button from paper-button, the component no longer
has support for aria-active-attribute. Instead we simply set the
expanded value via an element attribute binding.

Bug: 967793
Change-Id: I033c025aa25160ede9271cd5e8725e61630183f7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1798342Reviewed-by: Esmael Elmoslimany <aee@chromium.org>
Commit-Queue: Martin Robinson <mrobinson@igalia.com>
Cr-Commit-Position: refs/heads/master@{#695723}

chrome/browser/resources/settings/chromeos/os_settings_menu/os_settings_menu.html

@@ -225,7 +225,8 @@
           $i18n{pluginVmPageTitle}
         </div>
       </a>
-      <cr-button id="advancedButton" aria-active-attribute="aria-expanded"
+      <cr-button id="advancedButton"
+          aria-expanded$="[[boolToString_(advancedOpened)]]"
           on-click="onAdvancedButtonToggle_">
         <span>$i18n{advancedPageTitle}</span>
         <iron-icon icon="[[arrowState_(advancedOpened)]]">

chrome/browser/resources/settings/chromeos/os_settings_menu/os_settings_menu.js

@@ -108,4 +108,13 @@ Polymer({
     const submenu = /** @type {IronCollapseElement} */ (this.$.advancedSubmenu);
     return submenu.opened;
   },
+
+  /**
+   * @param {boolean} bool
+   * @return {string}
+   * @private
+   */
+  boolToString_: function(bool) {
+    return bool.toString();
+  },
 });

chrome/browser/resources/settings/settings_menu/settings_menu.html

@@ -176,7 +176,8 @@
         <iron-icon icon="settings:power-settings-new"></iron-icon>
         $i18n{onStartup}
       </a>
-      <cr-button id="advancedButton" aria-active-attribute="aria-expanded"
+      <cr-button id="advancedButton"
+          aria-expanded$="[[boolToString_(advancedOpened)]]"
           on-click="onAdvancedButtonToggle_"
           hidden="[[!pageVisibility.advancedSettings]]">
         <span>$i18n{advancedPageTitle}</span>

chrome/browser/resources/settings/settings_menu/settings_menu.js

@@ -95,4 +95,13 @@ Polymer({
     chrome.metricsPrivate.recordUserAction(
         'SettingsMenu_ExtensionsLinkClicked');
   },
+
+  /**
+   * @param {boolean} bool
+   * @return {string}
+   * @private
+   */
+  boolToString_: function(bool) {
+    return bool.toString();
+  },
 });