[MD Extensions] Add support for URL navigation

chrome/browser/resources/md_extensions/manager.html

 <link rel="import" href="chrome://resources/cr_elements/cr_drawer/cr_drawer.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_toolbar/cr_toolbar.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/promise_resolver.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-header-panel/paper-header-panel.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-toggle-button/paper-toggle-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animatable.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animated-pages.html">
 <link rel="import" href="chrome://extensions/detail_view.html">
 <link rel="import" href="chrome://extensions/drop_overlay.html">
 <link rel="import" href="chrome://extensions/error_page.html">
 <link rel="import" href="chrome://extensions/item_list.html">
 <link rel="import" href="chrome://extensions/keyboard_shortcuts.html">
 <link rel="import" href="chrome://extensions/load_error.html">
 <link rel="import" href="chrome://extensions/options_dialog.html">
 <link rel="import" href="chrome://extensions/pack_dialog.html">
+<link rel="import" href="chrome://extensions/page_state.html">
 <link rel="import" href="chrome://extensions/service.html">
 <link rel="import" href="chrome://extensions/sidebar.html">
 <link rel="import" href="chrome://extensions/toolbar.html">
 <link rel="stylesheet" href="chrome://resources/css/md_colors.css">
 
 <dom-module id="extensions-manager">
   <template>
     <style>
       [hidden] {
         display: none !important;
@@ skipping 58 matching lines @@
         </extensions-error-page>
       </neon-animated-pages>
       <extensions-options-dialog id="options-dialog">
       </extensions-options-dialog>
       <extensions-pack-dialog id="pack-dialog"></extensions-pack-dialog>
       <extensions-load-error id="load-error"></extensions-load-error>
     </paper-header-panel>
   </template>
   <script src="chrome://extensions/manager.js"></script>
 </dom-module>