Bail out on negative a0 values in FaxG4GetRow().

Bail out on negative a0 values in FaxG4GetRow().

BUG=648935

[Lei Zhang, 2016-09-23 07:57:10]

The CQ bit was checked by thestig@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-23 07:57:13]

Dry run: 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, 2016-09-23 08:06:47]

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

[commit-bot: I haz the power, 2016-09-23 08:06:48]

Dry run: Try jobs failed on following builders:
  linux_xfa on master.tryserver.client.pdfium (JOB_FAILED,
https://build.chromium.org/p/tryserver.client.pdfium/builders/linux_xfa/build...)

[kcwu, 2016-09-23 08:22:42]

kcwu@chromium.org changed reviewers:
+ kcwu@chromium.org

[kcwu, 2016-09-23 08:22:42]

I feel it should reject negative |columns| somewhere.

[kcwu, 2016-09-23 08:25:30]

On 2016/09/23 08:22:42, kcwu wrote:
> I feel it should reject negative |columns| somewhere.

p.s. negative |columns| is the source of other negative values.

[Lei Zhang, 2016-09-23 21:09:11]

Description was changed from

==========
Bail out on negative a0 values in FaxG4GetRow().

BUG=648935
==========

to

==========
Bail out on negative a0 values in FaxG4GetRow().

BUG=648935
==========