Store zone in microtask entry.

Store zone in microtask entry.

Avoids an extra stack-trace for doing zone.bindCallback (which is not overridable anyway).
Only optimizes cases where a new zone  overrides neither scheduleMicrotask nor errorHandler.

Committed: https://code.google.com/p/dart/source/detail?r=45125

[Lasse Reichstein Nielsen, 2015-02-02 12:32:38]

lrn@google.com changed reviewers:
+ iposva@chromium.org

[Lasse Reichstein Nielsen, 2015-02-02 12:32:39]

Reduces stack height in simple cases.

[Lasse Reichstein Nielsen, 2015-02-02 12:33:06]

lrn@google.com changed reviewers:
+ iposva@google.com
- iposva@chromium.org

[Ivan Posva, 2015-02-02 16:06:47]

LGTMwC -ip

https://codereview.chromium.org/891293003/diff/1/sdk/lib/async/schedule_micro...
File sdk/lib/async/schedule_microtask.dart (right):

https://codereview.chromium.org/891293003/diff/1/sdk/lib/async/schedule_micro...
sdk/lib/async/schedule_microtask.dart:71: // same Timer callback.
I am not clear what this comment is trying to tell me about Timer.run. Where and
what is this optimization?

[Lasse Reichstein Nielsen, 2015-02-23 08:01:39]

https://codereview.chromium.org/891293003/diff/1/sdk/lib/async/schedule_micro...
File sdk/lib/async/schedule_microtask.dart (right):

https://codereview.chromium.org/891293003/diff/1/sdk/lib/async/schedule_micro...
sdk/lib/async/schedule_microtask.dart:71: // same Timer callback.
I think the timer is long, long gone. This comment has been outdated since we
introduced the _scheduleImmeditate function.

[Lasse Reichstein Nielsen, 2015-02-23 08:01:40]

https://codereview.chromium.org/891293003/diff/1/sdk/lib/async/schedule_micro...
File sdk/lib/async/schedule_microtask.dart (right):

https://codereview.chromium.org/891293003/diff/1/sdk/lib/async/schedule_micro...
sdk/lib/async/schedule_microtask.dart:71: // same Timer callback.
I think the timer is long, long gone. This comment has been outdated since we
introduced the _scheduleImmeditate function.

[Lasse Reichstein Nielsen, 2015-04-14 07:37:57]

Committed patchset #2 (id:20001) manually as 45125 (presubmit successful).