Don't squash fixed-position elements into another fixed-position element that has a clip.

Don't squash fixed-position elements into another fixed-position element that has an
overflow clip.

Previously it checked for clip but not overflow clip.

BUG=409680
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=181495

[chrishtr, 2014-09-05 18:13:59]

chrishtr@chromium.org changed reviewers:
+ abarth@chromium.org, vollick@chromium.org

[abarth-chromium, 2014-09-05 20:09:32]

lgtm

[chrishtr, 2014-09-05 20:54:11]

Updated to narrow the logic to just position: fixed within position: fixed.
Otherwise, overflow should not clip. It's unclear what the spec requires for
nested position: fixed, but Chrome definitely goes with clipping and overflow
clipping, in both composited and non-composited modes. This change will align
squashing with that decision.

[chrishtr, 2014-09-05 20:54:15]

The CQ bit was checked by chrishtr@chromium.org

[commit-bot: I haz the power, 2014-09-05 20:54:29]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/chrishtr@chromium.org/543123003/20001

[commit-bot: I haz the power, 2014-09-06 02:55:11]

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

[commit-bot: I haz the power, 2014-09-06 02:55:12]

Exceeded time limit waiting for builds to trigger.

[pdr., 2014-09-06 03:00:00]

The CQ bit was checked by pdr@chromium.org

[commit-bot: I haz the power, 2014-09-06 03:01:19]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/chrishtr@chromium.org/543123003/20001

[chrishtr, 2014-09-06 03:50:29]

The CQ bit was checked by chrishtr@chromium.org

[chrishtr, 2014-09-06 03:50:29]

lgtm

[commit-bot: I haz the power, 2014-09-06 03:50:40]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/chrishtr@chromium.org/543123003/20001

[commit-bot: I haz the power, 2014-09-06 11:09:01]

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

[commit-bot: I haz the power, 2014-09-06 11:09:02]

Exceeded time limit waiting for builds to trigger.

[chrishtr, 2014-09-06 15:53:18]

The CQ bit was checked by chrishtr@chromium.org

[commit-bot: I haz the power, 2014-09-06 15:54:05]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/chrishtr@chromium.org/543123003/20001

[commit-bot: I haz the power, 2014-09-06 15:55:59]

Committed patchset #2 (id:20001) as 181495