Begin migrating the vm service from a rest-style interface to a json-rpc style interface.

runtime/observatory/lib/src/elements/library_view.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library library_view_element;
 
 import 'dart:async';
 import 'observatory_element.dart';
 import 'package:observatory/service.dart';
 import 'package:polymer/polymer.dart';
 
 
 @CustomTag('library-view')
 class LibraryViewElement extends ObservatoryElement {
   @published Library library;
 
   LibraryViewElement.created() : super.created();
 
-  Future<ServiceObject> eval(String text) {
-    return library.isolate.get(
-        library.id + "/eval?expr=${Uri.encodeComponent(text)}");
+  Future<ServiceObject> eval(String expression) {
+    return library.isolate.eval(library, expression);
   }
 
   void refresh(var done) {
     library.reload().whenComplete(done);
   }
 
   void refreshCoverage(var done) {
     library.refreshCoverage().whenComplete(done);
   }
 }