Remove compile time flag ORIENTATION_EVENT and use runtime flag instead.
Update layout test case to use runtime flag.

Depends on 131913003 & 132203007

BUG=181136, 331337

Review URL: https://codereview.chromium.org/137143002

git-svn-id: svn://svn.chromium.org/blink/trunk@165042 bbb929c8-8fbe-4397-9dbb-9b2b20218538