Use function names as service IDs, rather than indices.

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

+// Copyright (c) 2014, 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 functions_test;
+
+import 'package:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+import 'test_helper.dart';
+
+class Foo {
+  int a;
+}
+
+void script() {
+  new Foo().a = 42;
+}
+
+var tests = [
+
+(Isolate isolate) =>
+  isolate.rootLib.load().then((Library lib) {
+    expect(lib.classes.length, equals(1));
+    return lib.classes.first.load().then((Class fooClass) {
+      expect(fooClass.name, equals('Foo'));
+      return fooClass.get('functions/get%3Aa').then((ServiceFunction func) {
+        expect(func.name, equals('a'));
+        expect(func.kind, equals(FunctionKind.kImplicitGetterFunction));
+      });
+    });
+}),
+
+];
+
+main(args) => runIsolateTests(args, tests, testeeBefore: script);