MD Settings: rework how advanced UI shows

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

 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/html/assert.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-menu/paper-menu.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-menu/paper-submenu.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-ripple/paper-ripple.html">
 <link rel="import" href="/icons.html">
 <link rel="import" href="/route.html">
 <link rel="import" href="/settings_shared_css.html">
@@ skipping 118 matching lines @@
           </div>
 </if>
           <div data-path="/onStartup" on-tap="openPage_"
               hidden="[[!pageVisibility.onStartup]]">
             <iron-icon icon="settings:power-settings-new"></iron-icon>
             $i18n{onStartup}
           </div>
         </paper-menu>
       </div>
       <paper-submenu class="page-menu" id="advancedPage" actionable
-          opened="{{advancedOpened_}}"
+          opened="{{advancedOpened}}"
           hidden="[[!pageVisibility.advancedSettings]]">
         <div class="menu-trigger">
           <span>$i18n{advancedPageTitle}</span>
-          <iron-icon icon="[[arrowState_(advancedOpened_)]]"></iron-icon>
+          <iron-icon icon="[[arrowState_(advancedOpened)]]"></iron-icon>
           <paper-ripple></paper-ripple>
         </div>
         <paper-menu attr-for-selected="data-path" class="menu-content"
             id="advancedMenu" selected="[[currentRoute.path]]">
 <if expr="chromeos">
           <div data-path="/dateTime" on-tap="openPage_">
             <iron-icon icon="settings:access-time"></iron-icon>
             $i18n{dateTimePageTitle}
           </div>
 </if>
@@ skipping 45 matching lines @@
       <paper-submenu class="page-menu">
         <div about-selected$="[[aboutSelected_]]" class="menu-trigger"
             id="about-menu" on-tap="openPage_" data-path="/help">
           $i18n{aboutPageTitle}
         </div>
       </paper-submenu>
     </paper-menu>
   </template>
   <script src="settings_menu.js"></script>
 </dom-module>