Correct condition and flag state for skipping PLAY request.

Correct condition and flag state for skipping PLAY request.

* When PLAY request for casted video is skipped, this.playInProgress_ was not cleared and this inconsistent state prevented the video from being played. I cleared the flag in this case.
* When PAUSE reqeust is in progress, incoming PLAY request should not be skipped. So I added a condition to skip the PLAY request.

BUG=417520, 417538
TEST=manually tested the steps described in both bugs.

Committed: https://crrev.com/af8a4054eab230950711b506c096a69b5ed162e4
Cr-Commit-Position: refs/heads/master@{#297137}

[fukino, 2014-09-26 09:01:45]

fukino@chromium.org changed reviewers:
+ mtomasz@chromium.org

[fukino, 2014-09-26 09:02:16]

Tomasz, PTAL the CL? Thanks!

[mtomasz, 2014-09-29 00:25:05]

lgtm

[fukino, 2014-09-29 03:21:54]

fukino@chromium.org changed reviewers:
+ yoshiki@chromium.org

[fukino, 2014-09-29 03:21:55]

Thanks Tomasz!
@yoshiki, could you take a look, too?

[yoshiki, 2014-09-29 03:48:20]

lgtm thanks!

[fukino, 2014-09-29 03:48:37]

The CQ bit was checked by fukino@chromium.org

[commit-bot: I haz the power, 2014-09-29 03:48:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/603413003/1

[commit-bot: I haz the power, 2014-09-29 04:34:09]

Committed patchset #1 (id:1) as 943b2680a1a3ebf2e5a9a5b6faccbea8c89685cd

[commit-bot: I haz the power, 2014-09-29 04:36:05]

Patchset 1 (id:??) landed as
https://crrev.com/af8a4054eab230950711b506c096a69b5ed162e4
Cr-Commit-Position: refs/heads/master@{#297137}