GitLab

Add some basic perftests that track how long a given WebTouchEvent or
WebGestureEvent takes to propagate through the InputRouter.  This includes both
the time to send and the time to ack a given event, averaged over a typical
touch swipe or scroll gesture sequence.

BUG=339877
TBR=jam@chromium.org

Review URL: https://codereview.chromium.org/170913002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252079 0039d316-1c4b-4281-b951-d872f2087c98