Add Breakpoint class to Observatory.

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

 <link rel="import" href="../../../../packages/polymer/polymer.html">
 <link rel="import" href="observatory_element.html">
 
 <polymer-element name="script-inset" extends="observatory-element">
   <template>
     <style>
       .sourceInset {
       }
       .sourceBox {
         background-color: #f5f5f5;
@@ skipping 142 matching lines @@
       <template if="{{ line.bpt == null && !line.possibleBpt }}">
         <div class="emptyBreakpoint">&nbsp;</div>
       </template>
 
       <template if="{{ line.bpt == null && line.possibleBpt && !busy}}">
         <div class="possibleBreakpoint">
           <a on-click="{{ toggleBreakpoint }}">B</a>
         </div>
       </template>
 
-      <template if="{{ line.bpt != null && !line.bpt['resolved'] && !busy}}">
+      <template if="{{ line.bpt != null && !line.bpt.resolved && !busy}}">
         <div class="unresolvedBreakpoint">
           <a on-click="{{ toggleBreakpoint }}">B</a>
         </div>
       </template>
 
-      <template if="{{ line.bpt != null && line.bpt['resolved'] && !busy}}">
+      <template if="{{ line.bpt != null && line.bpt.resolved && !busy}}">
         <div class="resolvedBreakpoint">
           <a on-click="{{ toggleBreakpoint }}">B</a>
         </div>
       </template>
     </template> <!-- line != null -->
 
   </template>
 </polymer-element>
 
 <script type="application/dart" src="script_inset.dart"></script>