MD Settings: Stop using <option>'s |selected| HTML attribute in bindings.

chrome/browser/resources/settings/device_page/stylus.html

 <link rel="import" href="chrome://resources/html/action_link.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
 <link rel="import" href="../controls/settings_toggle_button.html">
 <link rel="import" href="../settings_shared_css.html">
 
 <dom-module id="settings-stylus">
   <template>
     <style include="settings-shared md-select">
       .settings-box > .secondary {
@@ skipping 40 matching lines @@
         $i18n{stylusNoteTakingAppWaitingForAndroid}
         <paper-spinner active></paper-spinner>
       </div>
 
       <div id="select-app" class="md-select-wrapper"
           hidden$="[[!showApps_(appChoices_, waitingForAndroid_)]]">
         <select id="menu" class="md-select"
             disabled="[[!prefs.settings.enable_stylus_tools.value]]"
             on-change="onSelectedAppChanged_">
           <template is="dom-repeat" items="[[appChoices_]]">
-            <option value="[[item.value]]" selected$="[[item.preferred]]">
+            <option value="[[item.value]]" selected="[[item.preferred]]">
               [[item.name]]
             </option>
           </template>
         </select>
         <span class="md-select-underline"></span>
       </div>
     </div>
 
     <!-- TODO(scottchen): Make a proper a[href].settings-box with
          icon-external (see: https://crbug.com/684005)-->
     <div class="settings-box two-line" on-tap="onFindAppsTap_" actionable
         hidden$="[[!prefs.arc.enabled.value]]">
       <div class="start">
         $i18n{stylusFindMoreAppsPrimary}
         <div class="secondary" id="stylusFindMoreAppsSecondary">
           $i18n{stylusFindMoreAppsSecondary}
         </div>
       </div>
       <button class="icon-external" is="paper-icon-button-light"
           aria-label="$i18n{stylusFindMoreAppsPrimary}"
           aria-describedby="stylusFindMoreAppsSecondary"></button>
     </div>
 
   </template>
   <script src="stylus.js"></script>
 </dom-module>