Remove dead code backing WheelEvent.webkitDirectionInvertedFromDevice

It always returns false. Make that explicit.

Review URL: https://codereview.chromium.org/415773008

git-svn-id: svn://svn.chromium.org/blink/trunk@178846 bbb929c8-8fbe-4397-9dbb-9b2b20218538
3 files changed