Include overflow when setting the logical flowthread bottom on the last column set.

Include overflow when setting the logical flowthread bottom on the last column set.

The logical height of the flow thread may be shorter than the start flowthread
offset of the last column set, if there's overflowing content. We used to have
expandToEncompassFlowThreadOverflow() to correct this, but let's include
overflow right away, instead of setting the bottom offset twice (first
incorrectly, then correctly).

This avoids an assertion failure (in this case the assertion was harmless,
though).

BUG=512362
R=dsinclair@chromium.org,jchaffraix@chromium.org,leviw@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=199952

[leviw_travelin_and_unemployed, 2015-08-03 21:10:00]

The CQ bit was checked by leviw@chromium.org

[leviw_travelin_and_unemployed, 2015-08-03 21:10:01]

lgtm

[commit-bot: I haz the power, 2015-08-03 21:10:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1266553002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1266553002/1

[commit-bot: I haz the power, 2015-08-03 23:07:28]

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

[commit-bot: I haz the power, 2015-08-03 23:07:29]

Try jobs failed on following builders:
  mac_blink_rel on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/mac_blink_rel/builds/64840)

[mstensho (USE GERRIT), 2015-08-04 06:36:26]

The CQ bit was checked by mstensho@opera.com

[commit-bot: I haz the power, 2015-08-04 06:36:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1266553002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1266553002/1

[commit-bot: I haz the power, 2015-08-04 07:14:12]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=199952