Make EventStreamSubscription DDC safe.

Make EventStreamSubscription DDC safe.

EventStreamSubscription.listen does a cast which is only working in
DDC because we're ignoring the failure.  This wraps the listener to
check the argument rather than casting the function.  Also picks up a
few misc changes to the main SDK that hadn't been merged into DDC.

BUG=
R=jacobr@google.com

Committed: https://github.com/dart-lang/sdk/commit/7ab0daeedf69a531497cb981bae364629ac87085

[Leaf, 2016-12-29 23:42:09]

leafp@google.com changed reviewers:
+ jacobr@google.com

[Jacob, 2017-01-03 15:23:39]

lgtm

[Leaf, 2017-01-09 12:13:47]

Description was changed from

==========
Make EventStreamSubscription DDC safe.

EventStreamSubscription.listen does a cast which is only working in
DDC because we're ignoring the failure.  This wraps the listener to
check the argument rather than casting the function.  Also picks up a
few misc changes to the main SDK that hadn't been merged into DDC.

BUG=
==========

to

==========
Make EventStreamSubscription DDC safe.

EventStreamSubscription.listen does a cast which is only working in
DDC because we're ignoring the failure.  This wraps the listener to
check the argument rather than casting the function.  Also picks up a
few misc changes to the main SDK that hadn't been merged into DDC.

BUG=
R=jacobr@google.com

Committed:
https://github.com/dart-lang/sdk/commit/7ab0daeedf69a531497cb981bae364629ac87085
==========

[Leaf, 2017-01-09 12:13:49]

Committed patchset #2 (id:20001) manually as
7ab0daeedf69a531497cb981bae364629ac87085 (presubmit successful).