Build Observatory as part of runtime

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

 <link rel="import" href="../../../../packages/polymer/polymer.html">
 <link rel="import" href="instance_ref.html">
 <link rel="import" href="observatory_element.html">
 <link rel="import" href="service_ref.html">
 
 <polymer-element name="field-ref" extends="service-ref">
   <template>
   <link rel="stylesheet" href="css/shared.css">
     <span>
       <template if="{{ ref.isStatic] }}">static</template>
       <template if="{{ ref.isFinal }}">final</template>
       <template if="{{ ref.isConst }}">const</template>
       <template if="{{ (ref.declaredType.name == 'dynamic' &&
                         !ref.isFinal && !ref.isConst) }}">
         var
       </template>
       <template if="{{ (ref.declaredType.name != 'dynamic') }}">
         <instance-ref ref="{{ ref.declaredType }}"></instance-ref>
       </template>
       <a on-click="{{ goto }}" title="{{ hoverText }}" _href="{{ url }}">{{ name }}</a>
     </span>
   </template>
 </polymer-element>
 
 <script type="application/dart" src="field_ref.dart"></script>