Fix new -Wconstant-conversion versions after clang r259271

Fix new -Wconstant-conversion versions after clang r259271

http://llvm.org/viewvc/llvm-project?view=revision&revision=259271 made clang's
-Wconversion stricter.  This (together with
https://chromium-review.googlesource.com/#/c/324860/) fixes all new instances
in a chromium/mac build.

No behavior change.

BUG=none

Committed: https://crrev.com/4e290e7f917999417eb38ed840c3dc2dde75881a
Cr-Commit-Position: refs/heads/master@{#372689}

[Nico, 2016-01-31 00:26:59]

thakis@chromium.org changed reviewers:
+ hans@chromium.org

[hans, 2016-02-01 17:02:17]

lgtm

[Nico, 2016-02-01 17:31:22]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2016-02-01 17:33:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1650843002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1650843002/1

[commit-bot: I haz the power, 2016-02-01 18:26:30]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-02-01 18:28:21]

Description was changed from

==========
Fix new -Wconstant-conversion versions after clang r259271

http://llvm.org/viewvc/llvm-project?view=revision&revision=259271 made clang's
-Wconversion stricter.  This (together with
https://chromium-review.googlesource.com/#/c/324860/) fixes all new instances
in a chromium/mac build.

No behavior change.

BUG=none
==========

to

==========
Fix new -Wconstant-conversion versions after clang r259271

http://llvm.org/viewvc/llvm-project?view=revision&revision=259271 made clang's
-Wconversion stricter.  This (together with
https://chromium-review.googlesource.com/#/c/324860/) fixes all new instances
in a chromium/mac build.

No behavior change.

BUG=none

Committed: https://crrev.com/4e290e7f917999417eb38ed840c3dc2dde75881a
Cr-Commit-Position: refs/heads/master@{#372689}
==========

[commit-bot: I haz the power, 2016-02-01 18:28:22]

Patchset 1 (id:??) landed as
https://crrev.com/4e290e7f917999417eb38ed840c3dc2dde75881a
Cr-Commit-Position: refs/heads/master@{#372689}