Fixes ClipboardRecentContentIOSTest on iOS 10.

Fixes ClipboardRecentContentIOSTest on iOS 10.

AddingNonStringRemovesCachedString was failing because it is now an error to
copy an empty UIImage to the pasteboard.

BUG=626686
Committed: https://crrev.com/850dda6b73575be3e6e34ed9da82263f6cc1d5f2
Cr-Commit-Position: refs/heads/master@{#404586}

[rohitrao (ping after 24h), 2016-07-08 20:35:22]

rohitrao@chromium.org changed reviewers:
+ jif@chromium.org, justincohen@chromium.org

[jif, 2016-07-10 09:00:16]

The CQ bit was checked by jif@chromium.org

[jif, 2016-07-10 09:00:16]

lgtm

[commit-bot: I haz the power, 2016-07-10 09:00:22]

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, 2016-07-11 01:14:11]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-11 01:14:12]

CQ bit was unchecked.

[commit-bot: I haz the power, 2016-07-11 01:16:41]

Description was changed from

==========
Fixes ClipboardRecentContentIOSTest on iOS 10.

AddingNonStringRemovesCachedString was failing because it is now an error to
copy an empty UIImage to the pasteboard.

BUG=626686
==========

to

==========
Fixes ClipboardRecentContentIOSTest on iOS 10.

AddingNonStringRemovesCachedString was failing because it is now an error to
copy an empty UIImage to the pasteboard.

BUG=626686

Committed: https://crrev.com/850dda6b73575be3e6e34ed9da82263f6cc1d5f2
Cr-Commit-Position: refs/heads/master@{#404586}
==========

[commit-bot: I haz the power, 2016-07-11 01:16:42]

Patchset 1 (id:??) landed as
https://crrev.com/850dda6b73575be3e6e34ed9da82263f6cc1d5f2
Cr-Commit-Position: refs/heads/master@{#404586}