Recover tracking pointer going up mid-gesture in shade.

Keep track of the pointer id used in driving the gesture. If
it happens to go up mid-gesture (another pointer is still down),
continue the gesture with another down pointer, instead of
abruptly jumping on next ACTION_MOVE.

Bug:10246050
Change-Id: Ia6e59658635fd696974fe415f37811d27da80519
1 file changed