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

chrome/browser/resources/settings/internet_page/network_summary_item.html

 <link rel="import" href="chrome://resources/cr_elements/cr_expand_button/cr_expand_button.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_network_list.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_network_list_item.html">
 <link rel="import" href="chrome://resources/html/action_link.html">
 <link rel="import" href="chrome://resources/html/action_link_css.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-a11y-keys-behavior/iron-a11y-keys-behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-collapse/iron-collapse.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
@@ skipping 60 matching lines @@
       </template>
 
       <div id="buttons" class="layout horizontal">
         <template is="dom-if"
             if="[[expandIsVisible_(deviceState, networkStateList)]]">
           <cr-expand-button id="expandListButton" expanded="{{expanded_}}">
           </cr-expand-button>
         </template>
         <template is="dom-if"
             if="[[showDetailsIsVisible_(deviceState, networkStateList)]]">
+          <!-- TODO(dbeam): this needs an aria-label. Maybe
+               [[activeNetworkState.name]]? -->
           <button class="subpage-arrow" is="paper-icon-button-light"
               on-tap="onShowDetailsTap_">
           </button>
         </template>
       </div>
 
       <template is="dom-if" if="[[enableToggleIsVisible_(deviceState)]]">
         <div class="secondary-action">
           <paper-toggle-button  id="deviceEnabledButton"
               checked="[[deviceIsEnabled_(deviceState)]]"
@@ skipping 20 matching lines @@
                 $i18n{knownNetworksButton}
               </a>
             </div>
           </template>
         </div>
       </iron-collapse>
     </template>
   </template>
   <script src="network_summary_item.js"></script>
 </dom-module>