Add transferHostTouchGestureToEmbedded API

Allow the host to transfer touch gesture to the embedded window.

Renamed focusGrantToken to inputTransferToken so it can be used to
transfer focus and gesture from host to embedded.

Test: SurfaceControlViewHostTests#testTransferHostTouchGestureToEmbedded
Bug: 303254234
Change-Id: Ie09121eccce46237d96b1a3233792bd3f3f3fd23