cc: Don't subtract transparent overlay from damage.

cc: Don't subtract transparent overlay from damage.

After processing overlay candidates we used to remove the overlay rects
from the damage rect.
The assumption was that all the overlays would be opaque.

Since we started allowing alpha blended overaly, we should avoid
subtracting from the damage when blending might be allowed.
Otherwise any element animating below a transparent overlay might
not be updated.

We haven't noticed any problem so far since partial update was disabled
on Mali. crrev.com/2829543003 enables empty swap, surfacing the problem
when the damage region is a subset of a transparent overlay.

BUG=705290
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2842383003
Cr-Commit-Position: refs/heads/master@{#467727}
Committed: https://chromium.googlesource.com/chromium/src/+/5f26315f43d9d4214df8af3deb263a02fc47db5d

[Daniele Castagna, 2017-04-27 00:44:53]

Description was changed from

==========
cc: Don't subtract transparent overlay from damage.

After processing overlay candidates we used to remove the overlay rects
from the damage rect.
The assumption was that all the overlays would be opaque.

Since we started allowing alpha blended overaly, we should avoid
subtracting from the damage when blending might be allowed.
Otherwise any element animating below a transparent overlay might
not be updated.

We haven't noticed any problem so far since partial update was disabled
on Mali. crrev.com/2829543003 enables empty swap, surfacing the problem
when the damage region is a subset of a transparent overlay.

BUG=705290
==========

to

==========
cc: Don't subtract transparent overlay from damage.

After processing overlay candidates we used to remove the overlay rects
from the damage rect.
The assumption was that all the overlays would be opaque.

Since we started allowing alpha blended overaly, we should avoid
subtracting from the damage when blending might be allowed.
Otherwise any element animating below a transparent overlay might
not be updated.

We haven't noticed any problem so far since partial update was disabled
on Mali. crrev.com/2829543003 enables empty swap, surfacing the problem
when the damage region is a subset of a transparent overlay.

BUG=705290
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

[Daniele Castagna, 2017-04-27 00:44:55]

The CQ bit was checked by dcastagna@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-04-27 00:45:31]

Dry run: CQ is trying da patch.

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

[Daniele Castagna, 2017-04-27 00:45:48]

dcastagna@chromium.org changed reviewers:
+ reveman@chromium.org

[reveman, 2017-04-27 00:48:10]

lgtm

[commit-bot: I haz the power, 2017-04-27 05:06:15]

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

[commit-bot: I haz the power, 2017-04-27 05:06:16]

Dry run: This issue passed the CQ dry run.

[Daniele Castagna, 2017-04-27 17:12:33]

The CQ bit was checked by dcastagna@chromium.org

[commit-bot: I haz the power, 2017-04-27 17:13:16]

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, 2017-04-27 17:50:15]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1493313153129430, "parent_rev":
"813697089a01c0a92b202cc6643d78a88e2f361e", "commit_rev":
"5f26315f43d9d4214df8af3deb263a02fc47db5d"}

[commit-bot: I haz the power, 2017-04-27 17:50:23]

Description was changed from

==========
cc: Don't subtract transparent overlay from damage.

After processing overlay candidates we used to remove the overlay rects
from the damage rect.
The assumption was that all the overlays would be opaque.

Since we started allowing alpha blended overaly, we should avoid
subtracting from the damage when blending might be allowed.
Otherwise any element animating below a transparent overlay might
not be updated.

We haven't noticed any problem so far since partial update was disabled
on Mali. crrev.com/2829543003 enables empty swap, surfacing the problem
when the damage region is a subset of a transparent overlay.

BUG=705290
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

to

==========
cc: Don't subtract transparent overlay from damage.

After processing overlay candidates we used to remove the overlay rects
from the damage rect.
The assumption was that all the overlays would be opaque.

Since we started allowing alpha blended overaly, we should avoid
subtracting from the damage when blending might be allowed.
Otherwise any element animating below a transparent overlay might
not be updated.

We haven't noticed any problem so far since partial update was disabled
on Mali. crrev.com/2829543003 enables empty swap, surfacing the problem
when the damage region is a subset of a transparent overlay.

BUG=705290
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2842383003
Cr-Commit-Position: refs/heads/master@{#467727}
Committed:
https://chromium.googlesource.com/chromium/src/+/5f26315f43d9d4214df8af3deb26...
==========

[commit-bot: I haz the power, 2017-04-27 17:50:24]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/5f26315f43d9d4214df8af3deb26...