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

runtime/observatory/test/graph_test.dart

Index: runtime/observatory/test/graph_test.dart
diff --git a/runtime/observatory/test/graph_test.dart b/runtime/observatory/test/graph_test.dart
index 64927814514308da243a8d32a625cc1417944959..db16681ae5e60b2514142834681a38f2599ae973 100644
--- a/runtime/observatory/test/graph_test.dart
+++ b/runtime/observatory/test/graph_test.dart
@@ -88,11 +88,11 @@ var tests = [
     expect(lib.classes.length, equals(1));
     Class fooClass = lib.classes.first;
     fooId = fooClass.vmCid;
-    isolate.get('graph');
+    isolate.invokeRpcNoUpgrade('requestHeapSnapshot', {});
     return completer.future;
   });
 },
 
 ];
 
-main(args) => runIsolateTests(args, tests, testeeBefore: script);
+main(args) => runIsolateTests(args, tests, testeeBefore: script);