MD User Manager: change last of i18n-* to $i18n{}

chrome/browser/resources/md_user_manager/control_bar.html

 <link rel="import" href="/profile_browser_proxy.html">
 <link rel="import" href="/shared_styles.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/iron-flex-layout-classes.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 
 <dom-module id="control-bar">
   <template>
     <style include="shared-styles iron-flex iron-flex-alignment iron-positioning">
       #container {
         -webkit-padding-end: 8px;
         -webkit-padding-start: 24px;
         align-items: center;
         min-height: 32px;
         padding-bottom: 12px;
         padding-top: 12px;
       }
 
       #logo {
         -webkit-margin-end: auto;
       }
     </style>
     <div id="container" class="layout horizontal end-justified">
       <div id="logo" class="product-logo" alt=""></div>
       <paper-button id="launchGuest" class="action secondary"
           on-tap="onLaunchGuestTap_"
-          i18n-content="browseAsGuest" hidden="[[!showGuest]]"></paper-button>
+          hidden="[[!showGuest]]">$i18n{browseAsGuest}</paper-button>
       <paper-button id="addUser" class="action secondary" on-tap="onAddUserTap_"
-          i18n-content="addUser" hidden="[[!showAddPerson]]"></paper-button>
+          hidden="[[!showAddPerson]]">$i18n{addUser}</paper-button>
     </div>
   </template>
   <script src="control_bar.js"></script>
 </dom-module>