MD Settings: Restore focus after exiting various subpages.

chrome/browser/resources/settings/printing_page/printing_page.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animatable.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
 <link rel="import" href="cloud_printers.html">
 <link rel="import" href="../route.html">
 <link rel="import" href="../settings_page/settings_animated_pages.html">
 <link rel="import" href="../settings_page/settings_subpage.html">
 <link rel="import" href="../settings_shared_css.html">
 <if expr="chromeos">
 <link rel="import" href="cups_printer_details_page.html">
 <link rel="import" href="cups_printers.html">
 </if>
 
 <dom-module id="settings-printing-page">
   <template>
     <style include="settings-shared"></style>
-    <settings-animated-pages id="pages" section="printing">
+    <settings-animated-pages id="pages" section="printing"
+        focus-config="[[focusConfig_]]">
       <array-selector id="arraySelector" items="{{cupsPrinters}}"
           selected="{{detailPrinter_}}">
       </array-selector>
       <neon-animatable route-path="default">
 <if expr="chromeos">
         <template is="dom-if" if="[[showCupsPrintingFeatures_]]">
           <div id="cupsPrinters" class="settings-box first"
               on-tap="onTapCupsPrinters_" actionable>
             <div class="start">$i18n{cupsPrintersTitle}</div>
             <button class="subpage-arrow" is="paper-icon-button-light"
@@ skipping 41 matching lines @@
             associated-control="[[$$('#cloudPrinters')]]"
             page-title="$i18n{cloudPrintersTitle}">
           <settings-cloud-printers prefs="{{prefs}}">
           </settings-cloud-printers>
         </settings-subpage>
       </template>
     </settings-animated-pages>
   </template>
   <script src="printing_page.js"></script>
 </dom-module>