nogncheck some includes guarded under OS_CHROMEOS

Past [1], 'ash/*' became a dependency tiedly coupled with
'is_chromeos'. This, for various reasons, helped to simplify the
dependency tree of mus+ash.

However, with the introduction of simple_wm [2], it should still be
possible to build and run Chrome/Ozone targeting LinuxOS
(not ChromeOS), with 'enable_package_mash_services' ON.

For that, this CL eases the gn checks for CHROMEOS specific header
inclusions in mash/package/mash_packaged_service.cc.

TEST=<out>/chrome --mash --ozone-platform={x11|wayland} --window-manager=simple_wm

[1] https://codereview.chromium.org/2549583002
[2] https://codereview.chromium.org/2511233002

BUG=666775

Review-Url: https://codereview.chromium.org/2620503002
Cr-Commit-Position: refs/heads/master@{#441978}
1 file changed