Build Observatory as part of runtime

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

-import 'package:observatory/service_io.dart';
-import 'package:unittest/unittest.dart';
-import 'test_helper.dart';
-
-import 'dart:profiler';
-
-void script() {
-  var counter = new Counter('a.b.c', 'description');
-  Metrics.register(counter);
-  counter.value = 1234.5;
-}
-
-var tests = [
-
-(Isolate isolate) =>
-  isolate.get('metrics/vm').then((ServiceMap metrics) {
-    expect(metrics['type'], equals('MetricList'));
-    var members = metrics['members'];
-    expect(members, isList);
-    expect(members.length, greaterThan(1));
-    var foundOldHeapCapacity = members.any((m) =>
-        m.name == 'heap.old.capacity');
-    expect(foundOldHeapCapacity, equals(true));
-}),
-
-(Isolate isolate) =>
-  isolate.get('metrics/vm/heap.old.used').then((ServiceMetric counter) {
-    expect(counter.type, equals('Counter'));
-    expect(counter.name, equals('heap.old.used'));
-}),
-
-(Isolate isolate) =>
-  isolate.get('metrics/vm/doesnotexist').then((DartError err) {
-    expect(err is DartError, isTrue);
-}),
-
-];
-
-main(args) => runIsolateTests(args, tests, testeeBefore: script);