Disabling un-supported stress tests on non-chromebooks

Adding APIs to check device type.

BUG=chromium:519078
TEST=Ran locally

Change-Id: I0b0f94d71c758ac4a06b5a5eca23258f5d319855
Reviewed-on: https://chromium-review.googlesource.com/293602
Reviewed-by: danny chan <dchan@chromium.org>
Commit-Queue: Rohit Makasana <rohitbm@chromium.org>
Tested-by: Rohit Makasana <rohitbm@chromium.org>
4 files changed