[MD settings] show blocked sites even when category is blocked

chrome/browser/resources/settings/site_settings/site_list.html

 <link rel="import" href="chrome://resources/cr_elements/cr_action_menu/cr_action_menu.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
 <link rel="import" href="/i18n_setup.html">
 <link rel="import" href="/icons.html">
 <link rel="import" href="/route.html">
 <link rel="import" href="/settings_shared_css.html">
@@ skipping 11 matching lines @@
 
       paper-icon-button {
         left: 8px;
         right: 8px;
       }
 
       .selectable {
         -webkit-user-select: text;
       }
     </style>
-    <div id="category" hidden>
+    <div id="category">
       <div class="settings-box first" hidden$="[[allSites]]">
         <h2 class="start">[[categoryHeader]]</h2>
         <paper-button class="secondary-button" id="icon" on-tap="onAddSiteTap_">
           $i18n{add}
         </paper-button>
       </div>
 
       <dialog is="cr-action-menu">
         <button class="dropdown-item" role="option" id="allow"
             on-tap="onAllowTap_" hidden$="[[!showAllowAction_]]">
@@ skipping 48 matching lines @@
                 </button>
               </div>
             </template>
           </div>
         </template>
       </div>
     </div>
   </template>
   <script src="site_list.js"></script>
 </dom-module>