MD Settings: label and describe a bunch of subpage/open-in-new buttons

chrome/browser/resources/settings/bluetooth_page/bluetooth_page.html

 <link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_pref_indicator.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/classes/iron-flex-layout.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animatable.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-toggle-button/paper-toggle-button.html">
 <link rel="import" href="../i18n_setup.html">
 <link rel="import" href="../icons.html">
 <link rel="import" href="../prefs/prefs.html">
 <link rel="import" href="../settings_page/settings_animated_pages.html">
 <link rel="import" href="../settings_page/settings_subpage.html">
 <link rel="import" href="../settings_shared_css.html">
 <link rel="import" href="bluetooth_subpage.html">
 
 <dom-module id="settings-bluetooth-page">
   <template>
     <style include="settings-shared">
     </style>
     <settings-animated-pages id="pages" section="bluetooth">
       <neon-animatable route-path="default">
         <div class="settings-box two-line" actionable on-tap="onTap_">
           <iron-icon icon="[[getIcon_(bluetoothEnabled_)]]"></iron-icon>
           <div class="middle">
-            <div>$i18n{bluetoothPageTitle}</div>
-            <div class="secondary">[[getDescription_(bluetoothEnabled_)]]</div>
+            $i18n{bluetoothPageTitle}
+            <div class="secondary" id="bluetoothSecondary">
+              [[getDescription_(bluetoothEnabled_)]]
+            </div>
           </div>
           <cr-policy-pref-indicator
               pref="[[prefs.cros.device.allow_bluetooth]]"
             hidden="[[prefs.cros.device.allow_bluetooth.value]]">
           </cr-policy-pref-indicator>
           <button class="subpage-arrow" is="paper-icon-button-light"
-              on-tap="onSubpageArrowTap_">
+              on-tap="onSubpageArrowTap_" aria-label="$i18n{bluetoothPageTitle}"
+              aria-describedby="bluetoothSecondary">
           </button>
           <div class="secondary-action">
             <paper-toggle-button id="enableBluetooth"
                 checked="{{bluetoothEnabled_}}"
                 disabled="[[!adapterState_.available]]" on-tap="stopTap_">
             </paper-toggle-button>
           </div>
         </div>
       </neon-animatable>
 
       <template is="dom-if" route-path="/bluetoothDevices">
         <settings-subpage associated-control="[[$$('#bluetoothDevices')]]"
             page-title="$i18n{bluetoothPageTitle}">
           <settings-bluetooth-subpage 
               adapter-state="[[adapterState_]]"
               bluetooth-enabled="{{bluetoothEnabled_}}"
               bluetooth="[[bluetooth]]"
               bluetooth-private="[[bluetoothPrivate]]">
           </settings-bluetooth-subpage>
         </settings-subpage>
       </template>
 
     </settings-animated-pages>
   </template>
   <script src="bluetooth_page.js"></script>
 </dom-module>