Allow pagination struts to push objects below the exact top of the next column.

Allow pagination struts to push objects below the exact top of the next column.

The top margin of a float may push its border box below the top of the next
column.

Similarly, a repeated table header may do the same to the first row in the next
column, to make room for itself above it.

The column balancer had assertions to boom at such situations, but it's pretty
clear now that it's an unreasonable requirements that sturts take us to the
exact top of the next column.

Added visual tests that crashed before (in debug). No behavioral changes here,
apart from the fact that the tests no longer crash.

Committed: https://crrev.com/99812493aac346077f265b7bebd0321d01503d80
Cr-Commit-Position: refs/heads/master@{#428047}

[mstensho (USE GERRIT), 2016-10-27 13:12:21]

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

[commit-bot: I haz the power, 2016-10-27 13:12:44]

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, 2016-10-27 15:00:09]

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

[commit-bot: I haz the power, 2016-10-27 15:00:10]

Dry run: This issue passed the CQ dry run.

[mstensho (USE GERRIT), 2016-10-27 15:05:05]

mstensho@opera.com changed reviewers:
+ eae@chromium.org

[eae, 2016-10-27 16:22:10]

OK, LGTM

[eae, 2016-10-27 16:22:14]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2016-10-27 16:22:35]

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, 2016-10-27 16:27:37]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-27 16:59:08]

Description was changed from

==========
Allow pagination struts to push objects below the exact top of the next column.

The top margin of a float may push its border box below the top of the next
column.

Similarly, a repeated table header may do the same to the first row in the next
column, to make room for itself above it.

The column balancer had assertions to boom at such situations, but it's pretty
clear now that it's an unreasonable requirements that sturts take us to the
exact top of the next column.

Added visual tests that crashed before (in debug). No behavioral changes here,
apart from the fact that the tests no longer crash.
==========

to

==========
Allow pagination struts to push objects below the exact top of the next column.

The top margin of a float may push its border box below the top of the next
column.

Similarly, a repeated table header may do the same to the first row in the next
column, to make room for itself above it.

The column balancer had assertions to boom at such situations, but it's pretty
clear now that it's an unreasonable requirements that sturts take us to the
exact top of the next column.

Added visual tests that crashed before (in debug). No behavioral changes here,
apart from the fact that the tests no longer crash.

Committed: https://crrev.com/99812493aac346077f265b7bebd0321d01503d80
Cr-Commit-Position: refs/heads/master@{#428047}
==========

[commit-bot: I haz the power, 2016-10-27 16:59:09]

Patchset 1 (id:??) landed as
https://crrev.com/99812493aac346077f265b7bebd0321d01503d80
Cr-Commit-Position: refs/heads/master@{#428047}