offsetParent() fails to consider continuations when searching for the parent.

offsetParent() fails to consider continuations when searching for the parent.

Block-level objects can have inline parents, but this triggers the
insertion of anonymous boxes and continuations, which offsetParent()
currently doesn't understand.

This change lets offsetParent() understand continuations better.
If an anonymous continuation is encountered when finding ancestors,
it will use the split inline as the ancestor, and continue searching
from there.

BUG=638177

[Karl Øygard, 2016-10-25 11:57:01]

The CQ bit was checked by karlo@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2016-10-25 11:57:17]

Dry run: 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, 2016-10-25 13:02:28]

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

[commit-bot: I haz the power, 2016-10-25 13:02:28]

Dry run: This issue passed the CQ dry run.

[Karl Øygard, 2016-10-26 08:41:56]

Description was changed from

==========
offsetParent() failed to consider continuations when searching for the parent.

Block-level objects can have inline parents, but this triggers the
insertion of anonymous boxes and continuations, which offsetParent()
didn't understand.

BUG=638177
==========

to

==========
offsetParent() fails to consider continuations when searching for the parent.

Block-level objects can have inline parents, but this triggers the
insertion of anonymous boxes and continuations, which offsetParent()
currently doesn't understand.

This change lets offsetParent() understand continuations better.
If an anonymous continuation is encountered when finding ancestors,
it will use the split inline as the ancestor, and continue searching
from there.

BUG=638177
==========

[Karl Øygard, 2016-10-28 07:50:32]

The CQ bit was checked by karlo@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2016-10-28 07:50:42]

Dry run: 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, 2016-10-28 09:01:06]

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

[commit-bot: I haz the power, 2016-10-28 09:01:07]

Dry run: This issue passed the CQ dry run.