Begin implementing a debugger page in Observatory.

runtime/bin/vmservice/observatory/lib/src/elements/nav_bar.html

 <link rel="import" href="../../../../packages/polymer/polymer.html">
 <link rel="import" href="action_link.html">
 <link rel="import" href="observatory_element.html">
 
 <polymer-element name="nav-bar" extends="observatory-element">
   <template>
     <link rel="stylesheet" href="css/shared.css">
     <style>
       nav {
         position: fixed;
@@ skipping 184 matching lines @@
     <nav-menu link="/vm" anchor="Observatory" last="{{ last }}">
       <nav-menu-item link="/vm-connect/" anchor="Connect to a different VM"></nav-menu-item>
       <content></content>
     </nav-menu>
   </template>
 </polymer-element>
 
 <polymer-element name="isolate-nav-menu" extends="observatory-element">
   <template>
     <nav-menu link="{{ hashLinkWorkaround }}" anchor="{{ isolate.name }}" last="{{ last }}">
-      <nav-menu-item link="{{ isolate.relativeLink('stacktrace') }}"
-                     anchor="stack trace"></nav-menu-item>
+      <nav-menu-item link="{{ '/debugger' + isolate.link }}"
+                     anchor="debugger"></nav-menu-item>
       <nav-menu-item link="{{ isolate.relativeLink('profile') }}"
                      anchor="cpu profile"></nav-menu-item>
       <nav-menu-item link="{{ isolate.relativeLink('allocationprofile') }}"
                      anchor="allocation profile"></nav-menu-item>
       <nav-menu-item link="{{ isolate.relativeLink('heapmap') }}"
                      anchor="heap map"></nav-menu-item>
       <nav-menu-item link="{{ isolate.relativeLink('debug/breakpoints') }}"
                      anchor="breakpoints"></nav-menu-item>
       <content></content>
     </nav-menu>
@@ skipping 131 matching lines @@
         Disconnected from VM
         <br><br>
         <a class="boxclose" on-click="{{ closeItem }}">&times;</a>
       </div>
     </template>
   </template>
 </polymer-element>
 
 
 <script type="application/dart" src="nav_bar.dart"></script>