Fix bugs in heapmap, binary payloads, 'address' request.

runtime/bin/vmservice/observatory/test/graph_test.dart

Index: runtime/bin/vmservice/observatory/test/graph_test.dart
===================================================================
--- runtime/bin/vmservice/observatory/test/graph_test.dart	(revision 42116)
+++ runtime/bin/vmservice/observatory/test/graph_test.dart	(working copy)
@@ -86,11 +86,8 @@
   });
   return isolate.rootLib.load().then((Library lib) {
     expect(lib.classes.length, equals(1));
-    // TODO(koda): Use vmCid.
     Class fooClass = lib.classes.first;
-    String prefix = "classes/";
-    // TODO(koda): Add method on Class to get numerical id.
-    fooId = int.parse(fooClass.id.substring(prefix.length));
+    fooId = fooClass.vmCid;
     isolate.get('graph');
     return completer.future;
   });