Fix a bug where PIXEL_UNPACK_BUFFER is cleared but never restored.

Fix a bug where PIXEL_UNPACK_BUFFER is cleared but never restored.

BUG=673929
TEST=test case from the bug
R=kbr@chromium.org,kainino@chromium.org
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2652653003
Cr-Commit-Position: refs/heads/master@{#445640}
(cherry picked from commit 6932383d121be06d4c40094b7f44b99026d2c396)

Review-Url: https://codereview.chromium.org/2662003002 .
Cr-Commit-Position: refs/branch-heads/2987@{#194}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed: https://chromium.googlesource.com/chromium/src/+/e6ff7696c74146965b4f7e083bf3d29e02f104c7

[Kai Ninomiya, 2017-01-30 20:25:07]

The CQ bit was checked by kainino@chromium.org

[commit-bot: I haz the power, 2017-01-30 20:25:51]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-01-30 20:25:51]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-01-30 20:25:52]

No L-G-T-M from a valid reviewer yet. 
CQ run can only be started by full committers or once the patch has
received an L-G-T-M from a full committer.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[Kai Ninomiya, 2017-01-30 22:04:17]

Description was changed from

==========
Fix a bug where PIXEL_UNPACK_BUFFER is cleared but never restored.

BUG=673929
TEST=test case from the bug
R=kbr@chromium.org,kainino@chromium.org
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2652653003
Cr-Commit-Position: refs/heads/master@{#445640}
(cherry picked from commit 6932383d121be06d4c40094b7f44b99026d2c396)
==========

to

==========
Fix a bug where PIXEL_UNPACK_BUFFER is cleared but never restored.

BUG=673929
TEST=test case from the bug
R=kbr@chromium.org,kainino@chromium.org
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2652653003
Cr-Commit-Position: refs/heads/master@{#445640}
(cherry picked from commit 6932383d121be06d4c40094b7f44b99026d2c396)

Review-Url: https://codereview.chromium.org/2662003002 .
Cr-Commit-Position: refs/branch-heads/2987@{#194}
Cr-Branched-From:
ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed:
https://chromium.googlesource.com/chromium/src/+/e6ff7696c74146965b4f7e083bf3...
==========

[Kai Ninomiya, 2017-01-30 22:04:20]

Committed patchset #4 (id:60001) manually as
e6ff7696c74146965b4f7e083bf3d29e02f104c7.