Switch to using SourceLocation universally in service protocol.

runtime/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 27 matching lines @@
       <div class="memberList">
         <div class="memberItem">
           <div class="memberName">library</div>
           <div class="memberValue">
             <library-ref ref="{{ cls.library }}"></library-ref>
           </div>
         </div>
         <div class="memberItem">
           <div class="memberName">script</div>
           <div class="memberValue">
-            <script-ref ref="{{ cls.script }}" pos="{{ cls.tokenPos }}">
-            </script-ref>
+            <source-link location="{{ cls.location }}"></source-link>
           </div>
         </div>
 
         <div class="memberItem">&nbsp;</div>
 
         <template if="{{ cls.superclass != null }}">
           <div class="memberItem">
             <div class="memberName">extends</div>
             <div class="memberValue">
               <class-ref ref="{{ cls.superclass }}"></class-ref>
@@ skipping 141 matching lines @@
                 </template>
               </template>
             </div>
           </div>
         </template>
     </div>
 
     <hr>
 
     <div class="content-centered-big">
-      <script-inset script="{{ cls.script }}"
-                    startPos="{{ cls.tokenPos }}"
-                    endPos="{{ cls.endTokenPos }}">
-      </script-inset>
+      <source-inset location="{{ cls.location }}">
+      </source-inset>
     </div>
 
     <view-footer></view-footer>
   </template>
 </polymer-element>
 
 <script type="application/dart" src="class_view.dart"></script>