Refactors parse_html_subset() into i18n_behavior.

chrome/browser/resources/md_user_manager/create_profile.html

 <link rel="import" href="chrome://md-user-manager/import_supervised_user.html">
 <link rel="import" href="chrome://md-user-manager/profile_browser_proxy.html">
 <link rel="import" href="chrome://md-user-manager/shared_styles.html">
 <link rel="import" href="chrome://resources/html/action_link.html">
 <link rel="import" href="chrome://resources/html/cr.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/html/util.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/iron-icons.html">
@@ skipping 185 matching lines @@
               </paper-listbox>
             </paper-dropdown-menu>
             <a id="import-user" is="action-link" on-tap="onImportUserTap_"
                 hidden="[[isImportUserLinkHidden_(createInProgress_,
                                                   signedInUserIndex_)]]">
               $i18n{importExistingSupervisedUserLink}
             </a>
           </template>
           <div id="sign-in-howto-message"
               hidden="[[isSignedIn_(signedInUsers_)]]"
-              inner-h-t-m-l="[[i18n('noSignedInUserMessage')]]">
+              inner-h-t-m-l="[[i18nAllowIDAttr_('noSignedInUserMessage')]]">
           </div>
         </template>
       </div>
       <div id="actions">
         <paper-spinner active="[[createInProgress_]]"></paper-spinner>
         <paper-button id="cancel" class="action secondary"
             on-tap="onCancelTap_">
           $i18n{cancel}
         </paper-button>
         <paper-button id="save" class="action primary" on-tap="onSaveTap_"
             disabled="[[isSaveDisabled_(createInProgress_, profileName_)]]">
           $i18n{createProfileConfirm}
         </paper-button>
       </div>
       <import-supervised-user id="importUserPopup"></import-supervised-user>
     </div>
   </template>
   <script src="chrome://md-user-manager/create_profile.js"></script>
 </dom-module>