Fix incorrect assumption about children's flexBasis

Fix incorrect assumption about children's flexBasis

The code to cache preferredMainAxisContentExtentForChild when possible
and re-use to avoid forcing layout was broken in the case that a child's
flex basis changed to cause it to be dependent on layout, triggering
an assert in debug. Just pushing it down the normal path fixes the
issue.

BUG=366185
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=183853

[leviw_travelin_and_unemployed, 2014-10-14 21:57:06]

leviw@chromium.org changed reviewers:
+ cbiesinger@chromium.org

[cbiesinger, 2014-10-14 22:08:47]

Good catch, but can you also add a test that more specifically tests flexbox?

[leviw_travelin_and_unemployed, 2014-10-16 00:01:09]

ptal!

[cbiesinger, 2014-10-17 00:16:04]

lgtm. thanks!

[leviw_travelin_and_unemployed, 2014-10-17 01:47:13]

The CQ bit was checked by leviw@chromium.org

[commit-bot: I haz the power, 2014-10-17 01:47:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/655053002/40001

[commit-bot: I haz the power, 2014-10-17 04:06:47]

Committed patchset #3 (id:40001) as 183853