MD Settings: Use $i18n{} templating in Languages pages

chrome/browser/resources/settings/languages_page/manage_languages_page.html

 <link rel="import" href="chrome://resources/html/assert.html">
 <link rel="import" href="chrome://resources/html/cr.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/iron-icons.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-list/iron-list.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-checkbox/paper-checkbox.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
 <link rel="import" href="chrome://md-settings/settings_shared_css.html">
 <link rel="import" href="languages.html">
 
 <dom-module id="settings-manage-languages-page">
   <template>
     <style include="settings-shared">
       .list-frame {
         display: flex;
         flex-direction: column;
         align-items: initial;
       }
 
       iron-list {
         height: 300px;
       }
     </style>
     <settings-languages languages="{{languages}}"></settings-languages>
     <div class="settings-box first content">
       <div class="start">
-        <h2 i18n-content="enabledLanguages"></h2>
+        <h2>$i18n{enabledLanguages}</h2>
         <div class="list-frame vertical-list">
           <template is="dom-repeat" items="{{languages.enabledLanguages}}">
             <div class="list-item">
               <div class="start" title="[[item.language.nativeDisplayName]]">
                 [[item.language.displayName]]
               </div>
               <paper-icon-button icon="clear" on-tap="onRemoveLanguageTap_"
                   hidden$="[[!canRemoveLanguage_(
                       item.language.code, prefs.intl.app_locale.value)]]">
               </paper-icon-button>
             </div>
           </template>
         </div>
-        <h2 i18n-content="allLanguages"></h2>
+        <h2>$i18n{allLanguages}</h2>
         <div class="list-frame vertical-list">
           <iron-list items="{{availableLanguages_}}" as="item">
             <template>
               <div class="list-item">
                 <paper-checkbox checked="[[item.enabled]]"
                     title$="[[item.nativeDisplayName]]"
                     disabled="[[!canRemoveLanguage_(
                         item.code, prefs.intl.app_locale.value)]]"
                     on-change="onLanguageCheckboxChange_">
                   [[item.displayName]]
                 </paper-checkbox>
               </div>
             </template>
           </iron-list>
         </div>
       </div>
     </div>
   </template>
   <script src="manage_languages_page.js"></script>
 </dom-module>