Refactoring of nav-notify

runtime/observatory/lib/src/elements/class_tree.html

 <link rel="import" href="../../../../packages/polymer/polymer.html">
 <link rel="import" href="nav_bar.html">
 <link rel="import" href="observatory_element.html">
 <link rel="import" href="class_ref.html">
 
 <polymer-element name="class-tree" extends="observatory-element">
   <template>
     <link rel="stylesheet" href="css/shared.css">
     <style>
       .table {
@@ skipping 13 matching lines @@
 
       th {
         text-align: left;
       }
     </style>
     <nav-bar>
       <top-nav-menu></top-nav-menu>
       <vm-nav-menu vm="{{ isolate.vm }}"></vm-nav-menu>
       <isolate-nav-menu isolate="{{ isolate }}"></isolate-nav-menu>
       <nav-menu link="{{ makeLink('/class-tree', isolate) }}" anchor="class hierarchy" last="{{ true }}"></nav-menu>
+      <nav-notify notifications="{{ app.notifications }}"></nav-notify>
     </nav-bar>
     <div class="content-centered">
       <h1>Class Hierarchy</h1>
       <table id="tableTree" class="table">
         <tbody id="tableTreeBody"></tbody>
       </table>
     </div>
   </template>
 </polymer-element>
 
 <script type="application/dart" src="class_tree.dart"></script>