Apply disable_post_sub_buffers_for_onscreen_surfaces only to mesa gl.

Apply disable_post_sub_buffers_for_onscreen_surfaces only to mesa gl.

Since this bug appears only on mesa for intel, limit workaround only to the mesa driver.

BUG=339493
Committed: https://crrev.com/16e7fae640eb254acd54533d865b3a01645607ac
Cr-Commit-Position: refs/heads/master@{#298280}

[ostap, 2014-09-30 20:46:01]

sl.ostapenko@samsung.com changed reviewers:
+ piman@chromium.org

[piman, 2014-09-30 20:49:18]

OSMesa != Mesa.

OSMesa is the software-only offscreen implementation that we use for tests
Intel hardware drivers are based on Mesa, but have nothing to do with OSMesa.

[ostap, 2014-10-06 15:45:14]

On 2014/09/30 20:49:18, piman (Very slow to review) wrote:
> OSMesa != Mesa.
> 
> OSMesa is the software-only offscreen implementation that we use for tests
> Intel hardware drivers are based on Mesa, but have nothing to do with OSMesa.

I updated patch.
Please, could you take another look?

Thanks.

[piman, 2014-10-06 18:01:51]

lgtm

[ostap, 2014-10-06 18:11:27]

The CQ bit was checked by sl.ostapenko@samsung.com

[commit-bot: I haz the power, 2014-10-06 18:14:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/612483004/20001

[commit-bot: I haz the power, 2014-10-06 18:21:08]

Committed patchset #2 (id:20001) as 8c6fceb44a7221babef3afd28bddf91db49cffe9

[commit-bot: I haz the power, 2014-10-06 18:23:04]

Patchset 2 (id:??) landed as
https://crrev.com/16e7fae640eb254acd54533d865b3a01645607ac
Cr-Commit-Position: refs/heads/master@{#298280}