Add breadcrumb for the VM.

runtime/observatory/lib/src/elements/heap_profile.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">
 <link rel="import" href="view_footer.html">
 
 <polymer-element name="heap-profile" extends="observatory-element">
 <template>
   <link rel="stylesheet" href="css/shared.css">
   <style>
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     }
     .nav-option {
       color: white;
       float: right;
       margin: 3px;
       padding: 8px;
     }
   </style>
   <nav-bar>
     <top-nav-menu></top-nav-menu>
+    <vm-nav-menu vm="{{ profile.isolate.vm }}"></vm-nav-menu>
     <isolate-nav-menu isolate="{{ profile.isolate }}"></isolate-nav-menu>
     <nav-menu link="{{ makeLink('/allocation-profiler', profile.isolate) }}" anchor="allocation profile" last="{{ true }}"></nav-menu>
     <nav-refresh callback="{{ resetAccumulator }}" label="Reset Accumulator"></nav-refresh>
     <nav-refresh callback="{{ refreshGC }}" label="GC"></nav-refresh>
     <nav-refresh callback="{{ refresh }}"></nav-refresh>
     <div class="nav-option">
       <input type="checkbox" checked="{{ autoRefresh }}">Auto-refresh on GC
     </div>
   </nav-bar>
   <div class="content">
@@ skipping 110 matching lines @@
       </thead>
       <tbody id="classTableBody">
       </tbody>
     </table>
     <view-footer></view-footer>
   </div>
 </template>
 </polymer-element>
 
 <script type="application/dart" src="heap_profile.dart"></script>