ozone: gbm: Fail earlier if device can't be opened

ozone: gbm: Fail earlier if device can't be opened

This crashes inside GbmBuffer::CreateBuffer due to NULL gbm_device. We
should check this earlier for a more informative crash.

BUG=410002
TEST=run chrome on link_freon
NOTRY=true

Committed: https://crrev.com/dd209e8c17ceb01fb575ce9701c056178e364729
Cr-Commit-Position: refs/heads/master@{#293175}

[spang, 2014-09-02 20:34:06]

spang@chromium.org changed reviewers:
+ dnicoara@chromium.org

[dnicoara, 2014-09-02 20:40:06]

lgtm

[spang, 2014-09-03 17:13:51]

The CQ bit was checked by spang@chromium.org

[commit-bot: I haz the power, 2014-09-03 17:17:15]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/spang@chromium.org/532873002/20001

[commit-bot: I haz the power, 2014-09-03 18:25:55]

Committed patchset #2 (id:20001) as 6b919af1f30d2dce1ecb8bcc4a797c48a09dd3a5

[commit-bot: I haz the power, 2014-09-10 03:27:01]

Patchset 2 (id:??) landed as
https://crrev.com/dd209e8c17ceb01fb575ce9701c056178e364729
Cr-Commit-Position: refs/heads/master@{#293175}