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

runtime/observatory/lib/src/elements/object_common.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 object_common_element;
 
 import 'dart:async';
 import 'observatory_element.dart';
 import 'package:observatory/service.dart';
 import 'package:polymer/polymer.dart';
 
 @CustomTag('object-common')
 class ObjectCommonElement extends ObservatoryElement {
   @published ServiceObject object;
   @published ServiceMap path;
   @published ServiceMap inboundReferences;
   @observable int retainedBytes = null;
 
   ObjectCommonElement.created() : super.created();
 
   // TODO(koda): Add no-arg "calculate-link" instead of reusing "eval-link".
   Future<ServiceObject> retainedSize(var dummy) {
-    return object.isolate.get(object.id + "/retained")
-        .then((Instance obj) {
-          retainedBytes = int.parse(obj.valueAsString);
-        });
+    return object.isolate.getRetainedSize(object).then((Instance obj) {
+      retainedBytes = int.parse(obj.valueAsString);
+    });
   }
 
-  Future<ServiceObject> retainingPath(var arg) {
-    return object.isolate.get(object.id + "/retaining_path?limit=$arg")
-        .then((ServiceObject obj) {
-          path = obj;
-        });
+  Future<ServiceObject> retainingPath(var limit) {
+    return object.isolate.getRetainingPath(object, limit).then((ServiceObject obj) {
+      path = obj;
+    });
   }
 
-  Future<ServiceObject> fetchInboundReferences(var arg) {
-    return object.isolate.get(object.id + "/inbound_references?limit=$arg")
+  Future<ServiceObject> fetchInboundReferences(var limit) {
+    return object.isolate.getInboundReferences(object, limit)
         .then((ServiceObject obj) {
            inboundReferences = obj;
         });
   }
 
   void refresh(Function onDone) {
     object.reload().whenComplete(onDone);
   }
 }