[css-grid] Avoid negative values as override containing block sizes

[css-grid] Avoid negative values as override containing block sizes

Add DCHECK to verify that we don't set negative values (other than -1
which means indefinite) as override containing block sizes.

Modified LayoutGrid::offsetAndBreadthForPositionedChild() to never
return negative breadths.

BUG=639620
Committed: https://crrev.com/83e4af423ad2b700659ef45ea0790ae2f8fd30ea
Cr-Commit-Position: refs/heads/master@{#413791}

[Manuel Rego, 2016-08-23 15:09:07]

rego@igalia.com changed reviewers:
+ cbiesinger@chromium.org, jfernandez@igalia.com, svillar@igalia.com

[cbiesinger, 2016-08-23 15:32:29]

lgtm

[Manuel Rego, 2016-08-23 15:40:04]

The CQ bit was checked by rego@igalia.com

[commit-bot: I haz the power, 2016-08-23 15:40:33]

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, 2016-08-23 18:25:46]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-23 18:27:26]

Description was changed from

==========
[css-grid] Avoid negative values as override containing block sizes

Add DCHECK to verify that we don't set negative values (other than -1
which means indefinite) as override containing block sizes.

Modified LayoutGrid::offsetAndBreadthForPositionedChild() to never
return negative breadths.

BUG=639620
==========

to

==========
[css-grid] Avoid negative values as override containing block sizes

Add DCHECK to verify that we don't set negative values (other than -1
which means indefinite) as override containing block sizes.

Modified LayoutGrid::offsetAndBreadthForPositionedChild() to never
return negative breadths.

BUG=639620

Committed: https://crrev.com/83e4af423ad2b700659ef45ea0790ae2f8fd30ea
Cr-Commit-Position: refs/heads/master@{#413791}
==========

[commit-bot: I haz the power, 2016-08-23 18:27:28]

Patchset 1 (id:??) landed as
https://crrev.com/83e4af423ad2b700659ef45ea0790ae2f8fd30ea
Cr-Commit-Position: refs/heads/master@{#413791}