[LayoutNG] Fix IsEmptyBlock check within block_layout_algorithm.

[LayoutNG] Fix IsEmptyBlock check within block_layout_algorithm.

Previoiusly we were just checking fragment.BlockSize() which was error
prone as:
<div style="height: 0px;">text</div>
... would have been considered an empty block.

Now the check uses the presence of the BfcOffset on the child's layout
result. If it isn't present, the child must be empty.

BUG=635619
Review-Url: https://codereview.chromium.org/2982643002
Cr-Commit-Position: refs/heads/master@{#486440}
Committed: https://chromium.googlesource.com/chromium/src/+/d82e3fae8315a1eee30b27522ccdb284bdd8ad3c

[ikilpatrick, 2017-07-12 23:07:11]

ikilpatrick@chromium.org changed reviewers:
+ cbiesinger@chromium.org, eae@chromium.org

[ikilpatrick, 2017-07-13 04:12:53]

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

[commit-bot: I haz the power, 2017-07-13 04:13:18]

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, 2017-07-13 06:04:32]

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

[commit-bot: I haz the power, 2017-07-13 06:04:33]

Dry run: This issue passed the CQ dry run.

[eae, 2017-07-13 18:02:11]

LGTM

[eae, 2017-07-13 18:04:41]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2017-07-13 18:04:50]

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, 2017-07-13 18:10:12]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1499969081961960,
"parent_rev": "ae67f19c066747ebc8f5cfe2e705b8169b508c21", "commit_rev":
"d82e3fae8315a1eee30b27522ccdb284bdd8ad3c"}

[commit-bot: I haz the power, 2017-07-13 18:10:23]

Description was changed from

==========
[LayoutNG] Fix IsEmptyBlock check within block_layout_algorithm.

Previoiusly we were just checking fragment.BlockSize() which was error
prone as:
<div style="height: 0px;">text</div>
... would have been considered an empty block.

Now the check uses the presence of the BfcOffset on the child's layout
result. If it isn't present, the child must be empty.

BUG=635619
==========

to

==========
[LayoutNG] Fix IsEmptyBlock check within block_layout_algorithm.

Previoiusly we were just checking fragment.BlockSize() which was error
prone as:
<div style="height: 0px;">text</div>
... would have been considered an empty block.

Now the check uses the presence of the BfcOffset on the child's layout
result. If it isn't present, the child must be empty.

BUG=635619

Review-Url: https://codereview.chromium.org/2982643002
Cr-Commit-Position: refs/heads/master@{#486440}
Committed:
https://chromium.googlesource.com/chromium/src/+/d82e3fae8315a1eee30b27522ccd...
==========

[commit-bot: I haz the power, 2017-07-13 18:10:25]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/chromium/src/+/d82e3fae8315a1eee30b27522ccd...