Can request CollectionViewModel itemAtIndexPath with nil

Can request CollectionViewModel itemAtIndexPath with nil

This CL makes sure that if CollectionViewModel is asked for the item at a nil
index path, it fails instead of treating it as requesting 0-0.

BUG=685621
Review-Url: https://codereview.chromium.org/2659593002
Cr-Commit-Position: refs/heads/master@{#446336}
Committed: https://chromium.googlesource.com/chromium/src/+/9899c468303d9472eeac076b486689753545f827

[gambard, 2017-01-26 13:35:54]

gambard@chromium.org changed reviewers:
+ lpromero@chromium.org

[gambard, 2017-01-26 13:35:55]

PTAL.

[lpromero, 2017-01-26 14:40:02]

lgtm

Lgtm but please add a unit test. You might even check that itemAtIndexPath
DCHECKs.

[gambard, 2017-01-26 15:39:56]

I only added a test for the hasItem, not for the DCHECK.

[gambard, 2017-01-26 15:39:59]

The CQ bit was checked by gambard@chromium.org

[gambard, 2017-01-26 15:39:59]

The patchset sent to the CQ was uploaded after l-g-t-m from
lpromero@chromium.org
Link to the patchset: https://codereview.chromium.org/2659593002/#ps20001
(title: "Add test")

[commit-bot: I haz the power, 2017-01-26 15:40:14]

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, 2017-01-26 15:49:22]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1485445199019760,
"parent_rev": "4c8bf6356505ca6e9c4dfefe2b40cc4395f7fcaa", "commit_rev":
"9899c468303d9472eeac076b486689753545f827"}

[commit-bot: I haz the power, 2017-01-26 15:49:57]

Description was changed from

==========
Can request CollectionViewModel itemAtIndexPath with nil

This CL makes sure that if CollectionViewModel is asked for the item at a nil
index path, it fails instead of treating it as requesting 0-0.

BUG=685621
==========

to

==========
Can request CollectionViewModel itemAtIndexPath with nil

This CL makes sure that if CollectionViewModel is asked for the item at a nil
index path, it fails instead of treating it as requesting 0-0.

BUG=685621

Review-Url: https://codereview.chromium.org/2659593002
Cr-Commit-Position: refs/heads/master@{#446336}
Committed:
https://chromium.googlesource.com/chromium/src/+/9899c468303d9472eeac076b4866...
==========

[commit-bot: I haz the power, 2017-01-26 15:49:57]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/9899c468303d9472eeac076b4866...