Revert of [i18n] chromeos login i18n-content to $i18n{}

chrome/browser/resources/chromeos/login/oobe_update.html

 <!-- Copyright 2016 The Chromium Authors. All rights reserved.
      Use of this source code is governed by a BSD-style license that can be
      found in the LICENSE file. -->
 
 <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/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-iconset-svg/iron-iconset-svg.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-progress/paper-progress.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-styles/color.html">
 
@@ skipping 12 matching lines @@
   </svg>
 </iron-iconset-svg>
 
 <dom-module name="oobe-update-md">
   <template>
     <link rel="stylesheet" href="oobe_update.css">
     <link rel="stylesheet" href="oobe_dialog_parameters.css">
     <oobe-dialog hidden="[[!checkingForUpdate]]">
       <iron-icon icon="oobe-update:googleg" class="oobe-icon"></iron-icon>
       <div class="header">
-        <h1 class="title">$i18n{checkingForUpdates}</h1>
+        <h1 class="title" i18n-content="checkingForUpdates"></h1>
         <div class="subtitle" id="checkingForUpdateCancelHint"
-            hidden="[[!cancelAllowed]]">
-          $i18n{cancelUpdateHint}
+            i18n-content="cancelUpdateHint" hidden="[[!cancelAllowed]]">
         </div>
       </div>
       <div class="footer flex layout vertical">
         <paper-progress id="checking-progress" indeterminate></paper-progress>
       </div>
     </oobe-dialog>
     <oobe-dialog hidden="[[checkingForUpdate]]">
       <iron-icon icon="oobe-update:googleg" class="oobe-icon"></iron-icon>
       <div class="header">
-        <h1 class="title">$i18n{updatingScreenTitle}</h1>
-        <div class="subtitle">$i18n{installingUpdateDesc}</div>
+        <h1 class="title" i18n-content="updatingScreenTitle"></h1>
+        <div class="subtitle" i18n-content="installingUpdateDesc"></div>
         <div class="subtitle" id="updatingCancelHint"
-            hidden="[[!cancelAllowed]]">
-          $i18n{cancelUpdateHint}
+            i18n-content="cancelUpdateHint" hidden="[[!cancelAllowed]]">
         </div>
       </div>
       <div class="footer flex layout vertical">
         <div id="update-upper-label">[[updateUpperLabel]]</div>
         <paper-progress min="0" max="100" value="[[progressValue]]">
         </paper-progress>
         <div id="estimated-time-left" class="progress-message"
             hidden="[[!estimatedTimeLeftShown]]">[[estimatedTimeLeft]]</div>
         <div id="progress-message" class="progress-message"
             hidden="[[!progressMessageShown]]">[[progressMessage]]</div>
       </div>
     </oobe-dialog>
   </template>
 </dom-module>