Teach the Observatory about Contexts. Factor out object graph information from the instance view.

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

 <link rel="import" href="../../../../packages/polymer/polymer.html">
 <link rel="import" href="curly_block.html">
 <link rel="import" href="eval_box.html">
 <link rel="import" href="eval_link.html">
 <link rel="import" href="field_ref.html">
 <link rel="import" href="function_ref.html">
 <link rel="import" href="instance_ref.html">
 <link rel="import" href="library_ref.html">
 <link rel="import" href="nav_bar.html">
 <link rel="import" href="observatory_element.html">
@@ skipping 74 matching lines @@
         <template if="{{ cls.name != cls.vmName }}">
           <div class="memberItem">
             <div class="memberName">vm name</div>
             <div class="memberValue">{{ cls.vmName }}</div>
           </div>
         </template>
       </div>
     </div>
 
     <template if="{{ cls.error != null }}">
-      <error-ref ref="{{ cls.error }}"></error>
+      <error-ref ref="{{ cls.error }}"></error-ref>
     </template>
 
     <hr>
 
     <div class="content">
       <template if="{{ cls.fields.isNotEmpty }}">
         fields ({{ cls.fields.length }})
         <curly-block expand="{{ cls.fields.length <= 8 }}">
           <div class="memberList">
             <template repeat="{{ field in cls.fields }}">
@@ skipping 86 matching lines @@
                   startPos="{{ cls.tokenPos }}"
                   endPos="{{ cls.endTokenPos }}">
     </script-inset>
 
     <br><br><br><br>
     <br><br><br><br>
   </template>
 </polymer-element>
 
 <script type="application/dart" src="class_view.dart"></script>