mac: Pass rubber-banding information to Blink.
Wheel-events should include information about whether they are allowed to
rubberband left or right. Previously, Blink inferred this information from
whether there was navigation history backwards or forwards. However, that is
insufficient, as a user can cancel a history-swipe, in which case rubberbanding
should be allowed in the given direction, even though history navigation is
possible.
This CL passes the information to Blink, which does not yet use it. No intended
functional change!
BUG=321437
TBR=joi@chromium.org
Review URL: https://codereview.chromium.org/
215163002
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@260879 0039d316-1c4b-4281-b951-d872f2087c98