[CSS Grid Layout] Testing content-distribution with spanning grid items.

[CSS Grid Layout] Testing content-distribution with spanning grid items.

The <content-distribution> values are applied on the grid tracks, which
are considered the alignment subject. When a grid item spans more than
one track, we stretch the grid item breadth to fill the space defined by
the <content-distribution> value.

This patch just adds a test to verify this is the current behavior, since
there is no test checking it out now.

BUG=249451, 376823
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=195488

[jfernandez, 2015-05-14 15:51:23]

jfernandez@igalia.com changed reviewers:
+ dsinclair@chromium.org, esprehn@chromium.org, jchaffraix@chromium.org

[Julien - ping for review, 2015-05-18 21:56:15]

The CQ bit was checked by jchaffraix@chromium.org

[Julien - ping for review, 2015-05-18 21:56:15]

lgtm

[commit-bot: I haz the power, 2015-05-18 21:56:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1142483003/1

[commit-bot: I haz the power, 2015-05-18 23:19:54]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=195488