Fixed issued in ViewGroup's transformation of MotionEvents to ensure
that the entire historical trace is transformed, not just the current
pointer.
Simplified the code in ViewGroup for splitting events across Views.
The new code also handles the case where some pointers are dispatched
to the ViewGroup in addition to its children whereas the previous
code would drop some pointers on the floor.
Change-Id: I56ac31903e1de8a9c376d9c935b7217b0c42d93e
20e987bfc3