Fix build with system ICU

Fix build with system ICU

Reported at https://bugs.gentoo.org/show_bug.cgi?id=602362 .

BUG=none

[Paweł Hajdan Jr., 2016-12-29 20:15:36]

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

[commit-bot: I haz the power, 2016-12-29 20:15:51]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Paweł Hajdan Jr., 2016-12-29 20:18:36]

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

[commit-bot: I haz the power, 2016-12-29 20:18:45]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Paweł Hajdan Jr., 2016-12-29 20:58:21]

phajdan.jr@chromium.org changed reviewers:
+ drott@chromium.org

[commit-bot: I haz the power, 2016-12-29 21:52:15]

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

[commit-bot: I haz the power, 2016-12-29 21:52:16]

Dry run: This issue passed the CQ dry run.

[Paweł Hajdan Jr., 2016-12-29 22:54:52]

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

[commit-bot: I haz the power, 2016-12-29 22:55:07]

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, 2016-12-30 00:21:20]

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

[commit-bot: I haz the power, 2016-12-30 00:21:21]

Dry run: This issue passed the CQ dry run.

[drott, 2016-12-30 14:07:08]

Thanks for trying to solve this, but I don't think this is the exactly right
fix. In the original bug report they're saying they're building with system ICU
58.2 - in which case this block of code should not be compiling, but no change
to our #if logic is needed. I believe the fact the defines are off and this
block compiles is something that needs to be fixed on the Gentoo build side. The
second problem however is that the own emoji functions currently do not build
because there is no operator that converts ICUError to a UErrorCode&.
Alternative fix proposal up in: https://codereview.chromium.org/2606183002

[drott, 2017-01-02 13:12:01]

As Phajdan LGTM'ed the new proposal in
https://codereview.chromium.org/2606183002 I am closing this CL.