Move ash/cros files under is_chromeos

Moved ash files under is_chromeos for eventual
non-ChromeOS compilation.

Bug: 896710
Test: Built on ChromeOS.
Change-Id: Ic03a4b6ce9edab2ce5b5d0c50f2cce46bd96ae50
Reviewed-on: https://chromium-review.googlesource.com/c/1291778
Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603154}
1 file changed