Refactoring of nav-notify

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

 <link rel="import" href="../../../../packages/polymer/polymer.html">
 <link rel="import" href="class_ref.html">
 <link rel="import" href="observatory_element.html">
 <link rel="import" href="nav_bar.html">
 
 <polymer-element name="heap-snapshot" extends="observatory-element">
 <template>
   <link rel="stylesheet" href="css/shared.css">
   <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('/heap-snapshot', isolate) }}" anchor="heap snapshot" last="{{ true }}"></nav-menu>
     <nav-refresh callback="{{ refresh }}"></nav-refresh>
+    <nav-notify notifications="{{ app.notifications }}"></nav-notify>
   </nav-bar>
   <style>
       /* general */
       .well {
         background-color: #ECECEC;
         padding: 0.2em;
       }
       .center {
         align-items: center;
         justify-content: center;
@@ skipping 166 matching lines @@
         </thead>
           <tbody id="treeBody"></tbody>
       </table>
     </div>
   </div>
   <view-footer></view-footer>
 </template>
 </polymer-element>
 
 <script type="application/dart" src="heap_snapshot.dart"></script>