mac: Fix a crash in the history swiper for magic mouse momentum events.
The 'trackSwipeWithEvent:' api throws an exception if the event passed in is a
momentum scroll event. We started using momentum scroll events in our logic for
magic trackpads, since we're working directly with hardware touches. We failed
to filter out momentum events when falling back to the 'trackSwipeWithEvent:'
api for magic mouse events.
BUG=331506
Review URL: https://codereview.chromium.org/
124313002
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243003 0039d316-1c4b-4281-b951-d872f2087c98