ozone: gbm: Fix broken DCHECK if !OS_CHROMEOS

ozone: gbm: Fix broken DCHECK if !OS_CHROMEOS

This doesn't even compile:

../../base/logging.h:523:23: error: invalid operands to binary expression ('basic_ostream<char, std::char_traits<char> >' and 'gfx::BufferUsage')
  ss << names << " (" << v1 << " vs. " << v2 << ")";
  ~~~~~~~~~~~~~~~~~~~ ^  ~~

BUG=530712
TEST=cast_shell_linux tryjob with gbm enabled by default

Committed: https://crrev.com/58abc5a09d52b275fe379813ac5b4180f4de4ef5
Cr-Commit-Position: refs/heads/master@{#348784}

[spang, 2015-09-14 23:42:41]

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

[dnicoara, 2015-09-14 23:44:05]

lgtm

[spang, 2015-09-14 23:44:10]

The CQ bit was checked by spang@chromium.org

[commit-bot: I haz the power, 2015-09-14 23:45:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1346513002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1346513002/1

[commit-bot: I haz the power, 2015-09-15 00:13:26]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-15 00:14:09]

Patchset 1 (id:??) landed as
https://crrev.com/58abc5a09d52b275fe379813ac5b4180f4de4ef5
Cr-Commit-Position: refs/heads/master@{#348784}

[commit-bot: I haz the power, 2015-09-23 12:39:56]

Patchset 1 (id:??) landed as
https://crrev.com/58abc5a09d52b275fe379813ac5b4180f4de4ef5
Cr-Commit-Position: refs/heads/master@{#348784}