Add watchlist for Device Orientation/Motion in Blink.

Watchlist for Device Orientation/Motion related code and
tests.

Review URL: https://codereview.chromium.org/68793002

git-svn-id: svn://svn.chromium.org/blink/trunk@161829 bbb929c8-8fbe-4397-9dbb-9b2b20218538