Implement `FutureOr<T>` for dart2js.

Implement `FutureOr<T>` for dart2js.

In dart2js, FutureOr<T> should simply be treated as `dynamic`.

Fixes #28011
BUG= http://dartbug.com/28011
R=johnniwinther@google.com, sigmund@google.com

Committed: https://github.com/dart-lang/sdk/commit/cc2eba8c2a23e1659ed26fcd37f9e114d43259fb

[floitsch, 2016-12-08 16:05:34]

floitsch@google.com changed reviewers:
+ sigmund@google.com

[floitsch, 2016-12-08 16:05:35]

Depends on https://codereview.chromium.org/2562703002/

Tests are here: https://codereview.chromium.org/2564563003/ for the tests.

[Siggi Cherem (dart-lang), 2016-12-08 18:51:39]

lgtm, thanks Florian!

[Johnni Winther, 2016-12-09 09:26:24]

johnniwinther@google.com changed reviewers:
+ johnniwinther@google.com

[Johnni Winther, 2016-12-09 09:26:24]

lgtm

[floitsch, 2016-12-12 14:21:08]

Description was changed from

==========
Implement `FutureOr<T>` for dart2js.

In dart2js, FutureOr<T> should simply be treated as `dynamic`.

Fixes #28011
BUG= http://dartbug.com/28011
==========

to

==========
Implement `FutureOr<T>` for dart2js.

In dart2js, FutureOr<T> should simply be treated as `dynamic`.

Fixes #28011
BUG= http://dartbug.com/28011
R=johnniwinther@google.com, sigmund@google.com

Committed:
https://github.com/dart-lang/sdk/commit/cc2eba8c2a23e1659ed26fcd37f9e114d43259fb
==========

[floitsch, 2016-12-12 14:21:09]

Committed patchset #2 (id:20001) manually as
cc2eba8c2a23e1659ed26fcd37f9e114d43259fb (presubmit successful).