Revert "Don't zone-register async callbacks for every await call in the VM."

tests/lib/async/async_await_zones_test.dart

Index: tests/lib/async/async_await_zones_test.dart
diff --git a/tests/lib/async/async_await_zones_test.dart b/tests/lib/async/async_await_zones_test.dart
deleted file mode 100644
index 210b05dee778929c0d7d3f3757afd3146e927214..0000000000000000000000000000000000000000
--- a/tests/lib/async/async_await_zones_test.dart
+++ /dev/null
@@ -1,142 +0,0 @@
-// Copyright (c) 2015, 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.
-
-// Test that async functions don't zone-register their callbacks for each
-// await. Async functions should register their callback once in the beginning
-// and then reuse it for all awaits in their body.
-// This has two advantages: it is faster, when there are several awaits (on
-// the Future class from dart:async), and it avoids zone-nesting when tracing
-// stacktraces.
-// See http://dartbug.com/23394 for more information.
-
-import 'dart:async';
-import 'package:expect/expect.dart';
-import 'package:async_helper/async_helper.dart';
-
-gee(i) async {
-  return await i;
-}
-
-bar() async* {
-  var i = 0;
-  while (true) yield await gee(i++);
-}
-
-
-awaitForTest() async {
-  var sum = 0;
-  await for (var x in bar().take(100)) {
-    sum += x;
-  }
-  Expect.equals(4950, sum);
-}
-
-awaitTest() async {
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  await null;
-  return await 499;
-}
-
-runTests() async {
-  await awaitTest();
-  await awaitForTest();
-}
-
-var depth = 0;
-
-var depthIncreases = 0;
-
-increaseDepth() {
-  depthIncreases++;
-  depth++;
-  // The async/await code should not register callbacks recursively in the
-  // then-calls. As such the depth should never grow too much. We don't want
-  // to commit to a specific value, since implementations still have some
-  // room in how async/await is implemented, but 20 should be safe.
-  Expect.isTrue(depth < 20);
-}
-
-registerCallback(Zone self, ZoneDelegate parent, Zone zone, f) {
-  var oldDepth = depth;
-  increaseDepth();
-  return parent.registerCallback(zone, () {
-    depth = oldDepth;
-    return f();
-  });
-}
-registerUnaryCallback(Zone self, ZoneDelegate parent, Zone zone, f) {
-  var oldDepth = depth;
-  increaseDepth();
-  return parent.registerUnaryCallback(zone, (x) {
-    depth = oldDepth;
-    return f(x);
-  });
-}
-registerBinaryCallback(Zone self, ZoneDelegate parent, Zone zone, f) {
-  var oldDepth = depth;
-  increaseDepth();
-  return parent.registerBinaryCallback(zone, (x, y) {
-    depth = oldDepth;
-    return f(x, y);
-  });
-}
-
-sm(Zone self, ZoneDelegate parent, Zone zone, f) {
-  var oldDepth = depth;
-  increaseDepth();
-  return parent.scheduleMicrotask(zone, () {
-    depth = oldDepth;
-    return f();
-  });
-}
-
-main() {
-  asyncStart();
-  var desc = new ZoneSpecification(
-      registerCallback: registerCallback,
-      registerUnaryCallback: registerUnaryCallback,
-      registerBinaryCallback: registerBinaryCallback,
-      scheduleMicrotask: sm
-      );
-  var future = runZoned(runTests, zoneSpecification: desc);
-  future.then((_) => asyncEnd());
-}