Switch to using SourceLocation universally in service protocol.

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 {
       }
       .sourceTable {
         display: table;
@@ skipping 61 matching lines @@
         background-color: #cac;
       }
       .resolvedBreakpoint {
         color: white;
         background-color: #e66;
       }
     </style>
   </template>
 </polymer-element>
 
+
+<polymer-element name="source-inset">
+<template>
+  <template if="{{ location != null }}">
+    <script-inset script="{{ location.script }}"
+                  startPos="{{ location.tokenPos }}"
+                  endPos="{{ location.endTokenPos }}"
+                  height="{{ height }}"
+                  currentPos="{{ currentPos }}"
+                  inDebuggerContext="{{ inDebuggerContext }}"
+                  variables="{{ variables }}">
+    </script-inset>
+  </template>
+</template>
+</polymer-element>
+
 <script type="application/dart" src="script_inset.dart"></script>