Close CAB when scrolled or back pressed

Bug: 33106791
Bug: 33106962
Test: manual - long press to display context menu on formula and
result, then drag to open history fragment. Long press on a
history result to display the context menu, then begin scrolling
or close history. CAB should close automatically in all cases.

Change-Id: Ibe3ceee2d06c5e15335a6938dbbd0ebbf444ce68