Cancel pending i/o when closing stdin on Windows

Cancel pending i/o when closing stdin on Windows

When cancelling a subscription to stdin, there may be pending I/O operation
that need to be explicitly cancelled before closing the stdin handle.

Otherwise the program would sit waiting for input (until CR is pressed).

Fixes dart-lang/pub#1502
Fixes #22940

R=zra@google.com

Committed: https://github.com/dart-lang/sdk/commit/2e1eeaf446cfe4bc2aa9b7dd4bf45d85f3c26072

[Florian Schneider, 2017-01-24 22:21:38]

fschneider@google.com changed reviewers:
+ zra@google.com

[Florian Schneider, 2017-01-24 22:21:39]

I tried adding a regression test, but the way stdin is wired up when running
tests with test.dart, the test always terminates properly without hanging. It
only reproduces when run standalone from the console.

[zra, 2017-01-24 22:25:05]

LGTM!

[Florian Schneider, 2017-01-24 22:47:44]

Description was changed from

==========
Cancel pending i/o when closing stdin on Windows

When cancelling a subscription to stdin, there may be pending I/O operation
that need to be explicitly cancelled before closing the stdin handle.

Otherwise the program would sit waiting for input (until CR is pressed).

Fixes dart-lang/pub#1502
Fixes #22940
==========

to

==========
Cancel pending i/o when closing stdin on Windows

When cancelling a subscription to stdin, there may be pending I/O operation
that need to be explicitly cancelled before closing the stdin handle.

Otherwise the program would sit waiting for input (until CR is pressed).

Fixes dart-lang/pub#1502
Fixes #22940

R=zra@google.com

Committed:
https://github.com/dart-lang/sdk/commit/2e1eeaf446cfe4bc2aa9b7dd4bf45d85f3c26072
==========

[Florian Schneider, 2017-01-24 22:47:46]

Committed patchset #1 (id:1) manually as
2e1eeaf446cfe4bc2aa9b7dd4bf45d85f3c26072 (presubmit successful).

[siva, 2017-01-24 23:04:23]

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

[siva, 2017-01-24 23:04:24]

Nice.