Do not set RootView's gesture handler on last ET_GESTURE_END
There might be cases that a RootView is trying to dispatch an
ET_GESTURE_END event and no gesture handler is set for that. In such
cases, after the event is handled by a view, it should not set that view
as the gesture handler for the RootView, since that gesture sequence is
finished.
BUG=334968
Review URL: https://codereview.chromium.org/
190663017
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256302 0039d316-1c4b-4281-b951-d872f2087c98