Fix treatment of layout overflow rect in ScrollAnchor bounds computation.

Fix treatment of layout overflow rect in ScrollAnchor bounds computation.

The relativeBounds helper assumed the anchor candidate's layout overflow rect
was positioned at 0,0 in its local coordinate space, but this is not always the
case, e.g. if positioned children have negative offsets.

BUG=685725
Review-Url: https://codereview.chromium.org/2662443003
Cr-Commit-Position: refs/heads/master@{#446485}
Committed: https://chromium.googlesource.com/chromium/src/+/9bcdced388956bfc8c137cfd20c830d30748946d

[skobes, 2017-01-26 20:31:12]

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

[commit-bot: I haz the power, 2017-01-26 20:31:40]

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

[skobes, 2017-01-26 20:36:34]

skobes@chromium.org changed reviewers:
+ szager@chromium.org

[szager1, 2017-01-26 21:54:26]

lgtm

[commit-bot: I haz the power, 2017-01-26 22:19:12]

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

[commit-bot: I haz the power, 2017-01-26 22:19:13]

Dry run: This issue passed the CQ dry run.

[skobes, 2017-01-26 22:59:49]

The CQ bit was checked by skobes@chromium.org

[commit-bot: I haz the power, 2017-01-26 23:00:52]

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, 2017-01-26 23:08:00]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1485471589493570, "parent_rev":
"c9251407fa9abe958dcbf2d72e7c25f8a422542c", "commit_rev":
"9bcdced388956bfc8c137cfd20c830d30748946d"}

[commit-bot: I haz the power, 2017-01-26 23:08:33]

Description was changed from

==========
Fix treatment of layout overflow rect in ScrollAnchor bounds computation.

The relativeBounds helper assumed the anchor candidate's layout overflow rect
was positioned at 0,0 in its local coordinate space, but this is not always the
case, e.g. if positioned children have negative offsets.

BUG=685725
==========

to

==========
Fix treatment of layout overflow rect in ScrollAnchor bounds computation.

The relativeBounds helper assumed the anchor candidate's layout overflow rect
was positioned at 0,0 in its local coordinate space, but this is not always the
case, e.g. if positioned children have negative offsets.

BUG=685725

Review-Url: https://codereview.chromium.org/2662443003
Cr-Commit-Position: refs/heads/master@{#446485}
Committed:
https://chromium.googlesource.com/chromium/src/+/9bcdced388956bfc8c137cfd20c8...
==========

[commit-bot: I haz the power, 2017-01-26 23:08:34]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/9bcdced388956bfc8c137cfd20c8...