Remove extra binder calls when not detecting gestures

- Previous refactoring meant that we were always fetching the running
  task to update the gesture state, even when you touch down in an
  area that is not in the gesture region (which is unnecessary).
  Also only transforming touch events (currently causes allocations)
  when we are actually handling a gesture.

Change-Id: I32e21c3e4d7113a782afce593711d9df62551bc8