Revert of Remove accelerated hardware decode blacklist entry for Mac OS X.

Revert of Remove accelerated hardware decode blacklist entry for Mac OS X. (patchset #2 id:20001 of https://codereview.chromium.org/849143002/)

Reason for revert:
This seems related to the regression here:
https://build.chromium.org/p/chromium.gpu/builders/Mac%20Release%20%28Intel%29/builds/45738

Original issue's description:
> Remove accelerated hardware decode blacklist entry for Mac OS X.
>
> Now that VTVideoDecodeAccelerator exists, this entry is not necessary.
>
> BUG=133828
>
> Committed: https://crrev.com/c0e69446b02848fce2e311662a43b8e782304ae3
> Cr-Commit-Position: refs/heads/master@{#311622}

TBR=scherkus@chromium.org,sievers@chromium.org,sandersd@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=133828
Committed: https://crrev.com/17202a5a52388cf6e0807a243364f6c995eb82a1
Cr-Commit-Position: refs/heads/master@{#311659}

[ricow1, 2015-01-15 13:55:42]

Created Revert of Remove accelerated hardware decode blacklist entry for Mac OS
X.

[commit-bot: I haz the power, 2015-01-15 13:56:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/853563003/1

[commit-bot: I haz the power, 2015-01-15 13:56:58]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-15 13:58:34]

Patchset 1 (id:??) landed as
https://crrev.com/17202a5a52388cf6e0807a243364f6c995eb82a1
Cr-Commit-Position: refs/heads/master@{#311659}

[sandersd (OOO until July 31), 2015-01-15 20:29:53]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/857433002/ by sandersd@chromium.org.

The reason for reverting is: Test failure corrected by:

https://crrev.com/81a119ffed1edbb462b51ed5b25a421bb9a03298
Cr-Commit-Position: refs/heads/master@{#311726}.