Fix behavior when listening multiple times to a broadcast take/skip stream.

Fix behavior when listening multiple times to a broadcast take/skip stream.

Turns out the existing behavior was badly broken.
A broadcastStream.take(10) would only produce ten events total, no matter how
many listeners were attached, beacuse the counter was on the stream, not the
subscription.

R=floitsch@google.com

Committed: https://code.google.com/p/dart/source/detail?r=43755

[Lasse Reichstein Nielsen, 2015-02-13 12:43:45]

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

[Lasse Reichstein Nielsen, 2015-02-13 12:43:46]

All tests run after the change, so I'll add tests for the broken behavior too.

[floitsch, 2015-02-13 13:52:56]

LGTM.

https://codereview.chromium.org/920373003/diff/20001/sdk/lib/async/stream_pip...
File sdk/lib/async/stream_pipe.dart (right):

https://codereview.chromium.org/920373003/diff/20001/sdk/lib/async/stream_pip...
sdk/lib/async/stream_pipe.dart:348: * Use by several different classes, some
storeing an integer, others a bool.
storing

[Lasse Reichstein Nielsen, 2015-02-13 13:56:35]

New patchsets have been uploaded after l-g-t-m from floitsch@google.com

[Lasse Reichstein Nielsen, 2015-02-13 13:59:49]

Committed patchset #3 (id:40001) manually as 43755 (presubmit successful).