Handle null in value list in getLayeredShorthandValue

Handle null in value list in getLayeredShorthandValue

By setting the backgroundRepeatY property to null it can
happen that accessing that CSS value returns a null pointer.
In that case simply bail out early.

BUG=445825
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=188842

[rwlbuis, 2015-01-13 00:00:05]

rob.buis@samsung.com changed reviewers:
+ timloh@chromium.org

[rwlbuis, 2015-01-13 00:00:05]

PTAL. I am not yet sure this is the correct fix. For a start, I am surprised
that backgroundRepeatY can be set like
that? I could not find any reference to that after a quick google search.

[rwlbuis, 2015-01-15 23:14:16]

On 2015/01/13 00:00:05, rwlbuis wrote:
> PTAL. I am not yet sure this is the correct fix. For a start, I am surprised
> that backgroundRepeatY can be set like
> that? I could not find any reference to that after a quick google search.

ping :)

[Timothy Loh, 2015-01-16 03:25:20]

On 2015/01/15 23:14:16, rwlbuis wrote:
> On 2015/01/13 00:00:05, rwlbuis wrote:
> > PTAL. I am not yet sure this is the correct fix. For a start, I am surprised
> > that backgroundRepeatY can be set like
> > that? I could not find any reference to that after a quick google search.
> 
> ping :)

Wouldn't it be more correct to try and get the checkShorthandAvailable flag to
always be true, so we wouldn't even get to there with a null backgroundRepeatY?

[rwlbuis, 2015-01-16 20:18:02]

On 2015/01/16 03:25:20, Timothy Loh wrote:
> On 2015/01/15 23:14:16, rwlbuis wrote:
> > On 2015/01/13 00:00:05, rwlbuis wrote:
> > > PTAL. I am not yet sure this is the correct fix. For a start, I am
surprised
> > > that backgroundRepeatY can be set like
> > > that? I could not find any reference to that after a quick google search.
> > 
> > ping :)
> 
> Wouldn't it be more correct to try and get the checkShorthandAvailable flag to
> always be true, so we wouldn't even get to there with a null
backgroundRepeatY?

You are right, I did not know this code very well.
It did mean changing a lot of tests since background will be serialized as "" if
one
of the subcomponents is empty. However that does seem to match FireFox.

[rwlbuis, 2015-01-22 15:17:35]

On 2015/01/16 20:18:02, rwlbuis wrote:
> On 2015/01/16 03:25:20, Timothy Loh wrote:
> > On 2015/01/15 23:14:16, rwlbuis wrote:
> > > On 2015/01/13 00:00:05, rwlbuis wrote:
> > > > PTAL. I am not yet sure this is the correct fix. For a start, I am
> surprised
> > > > that backgroundRepeatY can be set like
> > > > that? I could not find any reference to that after a quick google
search.
> > > 
> > > ping :)
> > 
> > Wouldn't it be more correct to try and get the checkShorthandAvailable flag
to
> > always be true, so we wouldn't even get to there with a null
> backgroundRepeatY?
> 
> You are right, I did not know this code very well.
> It did mean changing a lot of tests since background will be serialized as ""
if
> one
> of the subcomponents is empty. However that does seem to match FireFox.

ping

[Timothy Loh, 2015-01-22 23:01:11]

On 2015/01/22 15:17:35, rwlbuis wrote:
> On 2015/01/16 20:18:02, rwlbuis wrote:
> > On 2015/01/16 03:25:20, Timothy Loh wrote:
> > > On 2015/01/15 23:14:16, rwlbuis wrote:
> > > > On 2015/01/13 00:00:05, rwlbuis wrote:
> > > > > PTAL. I am not yet sure this is the correct fix. For a start, I am
> > surprised
> > > > > that backgroundRepeatY can be set like
> > > > > that? I could not find any reference to that after a quick google
> search.
> > > > 
> > > > ping :)
> > > 
> > > Wouldn't it be more correct to try and get the checkShorthandAvailable
flag
> to
> > > always be true, so we wouldn't even get to there with a null
> > backgroundRepeatY?
> > 
> > You are right, I did not know this code very well.
> > It did mean changing a lot of tests since background will be serialized as
""
> if
> > one
> > of the subcomponents is empty. However that does seem to match FireFox.
> 
> ping

lgtm

[rwlbuis, 2015-01-22 23:02:16]

The CQ bit was checked by rob.buis@samsung.com

[commit-bot: I haz the power, 2015-01-22 23:03:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/846933002/60001

[commit-bot: I haz the power, 2015-01-23 01:04:22]

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

[commit-bot: I haz the power, 2015-01-23 01:04:23]

Exceeded time limit waiting for builds to trigger.

[rwlbuis, 2015-01-23 01:13:21]

The CQ bit was checked by rob.buis@samsung.com

[commit-bot: I haz the power, 2015-01-23 01:14:12]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/846933002/60001

[commit-bot: I haz the power, 2015-01-23 01:42:00]

Committed patchset #4 (id:60001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=188842