10/ Migrate shared state to the gesture state

- Instead of a shared state which is written into, gestures update their
  own gesture state and that state is passed to the next gesture.
- The existing shared state encoded the final end target (which is
  currently directly correlated with canGestureBeContinued). If we move
  the end target calculations to the GestureState, the handlers can listen
  for those changes and we can use the previous gesture state to decide
  which consumer to choose.  In addition, we move over the interrupted-
  finish-launch-task id.

Bug: 141886704

Change-Id: Icb6a3815c16b23692dbcde316114bd3cea06634e
Signed-off-by: Winson Chung <winsonc@google.com>