gpu: Correct GMB format for GL_RGB BackTexture.

gpu: Correct GMB format for GL_RGB BackTexture.

When allocating a GMB for the offscreen color texture we should
pick the correct GMB format based on the internalformat of the fb.

We used to always allocate RGBA, with this patch we'll allocate
RGBX in case the internal foramt is GL_RGB.

BUG=680851, chrome-os-partner:62472
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/2665963002
Cr-Commit-Position: refs/heads/master@{#447340}
(cherry picked from commit 5a771c396bea52c449c4e22a15b93973f60488e0)

Review-Url: https://codereview.chromium.org/2671523002 .
Cr-Commit-Position: refs/branch-heads/2987@{#250}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed: https://chromium.googlesource.com/chromium/src/+/3aa2f5150aa815142dc94c8a3e8ab52f1ec23573

[Daniele Castagna, 2017-02-01 19:18:13]

Description was changed from

==========
gpu: Correct GMB format for GL_RGB BackTexture.

When allocating a GMB for the offscreen color texture we should
pick the correct GMB format based on the internalformat of the fb.

We used to always allocate RGBA, with this patch we'll allocate
RGBX in case the internal foramt is GL_RGB.

BUG=680851,chrome-os-partner:62472
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/2665963002
Cr-Commit-Position: refs/heads/master@{#447340}
(cherry picked from commit 5a771c396bea52c449c4e22a15b93973f60488e0)
==========

to

==========
gpu: Correct GMB format for GL_RGB BackTexture.

When allocating a GMB for the offscreen color texture we should
pick the correct GMB format based on the internalformat of the fb.

We used to always allocate RGBA, with this patch we'll allocate
RGBX in case the internal foramt is GL_RGB.

BUG=680851,chrome-os-partner:62472
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/2665963002
Cr-Commit-Position: refs/heads/master@{#447340}
(cherry picked from commit 5a771c396bea52c449c4e22a15b93973f60488e0)

Review-Url: https://codereview.chromium.org/2671523002 .
Cr-Commit-Position: refs/branch-heads/2987@{#250}
Cr-Branched-From:
ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed:
https://chromium.googlesource.com/chromium/src/+/3aa2f5150aa815142dc94c8a3e8a...
==========

[Daniele Castagna, 2017-02-01 19:18:14]

Committed patchset #1 (id:1) manually as
3aa2f5150aa815142dc94c8a3e8ab52f1ec23573.