gbm: make NativePixmap RefCountedThreadSafe

gbm: make NativePixmap RefCountedThreadSafe

NativePixmap is created/deleted in IO thread and used in main thread to create
GL Image. So NativePixmap must be thread safe ref counted.

BUG=472610
Committed: https://crrev.com/cde2551f434c89651e7a1a739f90dfcedf9d4b29
Cr-Commit-Position: refs/heads/master@{#323234}

[dshwang, 2015-04-01 12:34:29]

dongseong.hwang@intel.com changed reviewers:
+ reveman@chromium.org, spang@chromium.org

[dshwang, 2015-04-01 12:34:30]

reveman@, could you review as zero/one-copy expert?
spang@, could you review as owner?

[reveman, 2015-04-01 13:37:00]

Do we need to modify the ref count on the main thread? If that's not the case
then I think it would be better to fix this issue by avoiding that.

[dshwang, 2015-04-01 14:10:32]

On 2015/04/01 13:37:00, reveman wrote:
> Do we need to modify the ref count on the main thread? If that's not the case
> then I think it would be better to fix this issue by avoiding that.

Yes, GLImageOzeonNativePixmap ref/unref it in main thread,
https://code.google.com/p/chromium/codesearch#chromium/src/ui/ozone/gpu/gpu_m...

GLImageOzeonNativePixmap uses native pixmap for ScheduleOverlayPlane(), so looks
difficult to avoid that.

[reveman, 2015-04-01 14:24:26]

lgtm

[spang, 2015-04-01 14:27:39]

The CQ bit was checked by spang@chromium.org

[spang, 2015-04-01 14:27:40]

The CQ bit was unchecked by spang@chromium.org

[spang, 2015-04-01 14:27:45]

The CQ bit was checked by spang@chromium.org

[spang, 2015-04-01 14:27:46]

lgtm

[commit-bot: I haz the power, 2015-04-01 14:28:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1056493002/1

[dshwang, 2015-04-01 14:28:07]

On 2015/04/01 14:27:46, spang wrote:
> lgtm

thx for reviewing!

[commit-bot: I haz the power, 2015-04-01 14:30:58]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-01 14:31:40]

Patchset 1 (id:??) landed as
https://crrev.com/cde2551f434c89651e7a1a739f90dfcedf9d4b29
Cr-Commit-Position: refs/heads/master@{#323234}