libchrome: Use different condition to build libmojo.

New USE flag "mojo" is being introduced, so libmojo build
can depend on it.
The dependency between cyrpto and mojo will be handled in ebuild.

BUG=chromium:910002
TEST=Build locally.

Change-Id: Ib127d22d6a94491efaca1a64953727ef7a1d0b40
Reviewed-on: https://chromium-review.googlesource.com/1454004
Commit-Ready: Hidehiko Abe <hidehiko@chromium.org>
Tested-by: Hidehiko Abe <hidehiko@chromium.org>
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
1 file changed