CDM FileIOTest: Work around flakiness by not closing during read/write.

CDM FileIOTest: Work around flakiness by not closing during read/write.

The flakiness is caused by issue 415401. Temporarily disable tests that close
the FileIO during pending read or write.

This also reenables ECKEncryptedMediaTest.FileIOTest by reverting commit
5af9a9c9d2d559014734c2eb2247d42f3fc0e740.

BUG=415401, 415742
Committed: https://crrev.com/0c617e11d065c8104e9b96775363bdeb7dd1e68b
Cr-Commit-Position: refs/heads/master@{#295726}

[xhwang, 2014-09-19 03:58:30]

xhwang@chromium.org changed reviewers:
+ dbeam@chromium.org, ddorwin@chromium.org, erg@chromium.org

[xhwang, 2014-09-19 03:58:30]

PTAL

[ddorwin, 2014-09-19 16:23:12]

lgtm

[xhwang, 2014-09-19 16:48:01]

The CQ bit was checked by xhwang@chromium.org

[commit-bot: I haz the power, 2014-09-19 16:49:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/582233003/1

[commit-bot: I haz the power, 2014-09-19 17:33:34]

Committed patchset #1 (id:1) as 3dcdfbdb09c1bcd84784be6b2fb413fc687e37f9

[commit-bot: I haz the power, 2014-09-19 17:34:16]

Patchset 1 (id:??) landed as
https://crrev.com/0c617e11d065c8104e9b96775363bdeb7dd1e68b
Cr-Commit-Position: refs/heads/master@{#295726}