input: set the current surface correctly for tablet events
It ignored subsurfaces and always used the root surface of the window.
BUG: 499576 CCBUG: 498386 (cherry picked from commit e3e6af69)
It ignored subsurfaces and always used the root surface of the window.
BUG: 499576 CCBUG: 498386 (cherry picked from commit e3e6af69)