Add transferTouch api

The new api will be similar to "transferTouchFocus" and
"pilferPointers".

In the new api, we will be transferring touch, wherever it might be,
to the specified window. This will be used in the case where the app
is fullscreen, and the user swipes down to check notifications.

Currently, the behaviour is like this: user swipes once to show the
status bar, and then swipes again to show the notification shade.

The desired experience is for user to swipe once to show the
notification shade.

This new api will allow the StatusBar to transfer touch to the
notification shade, so that it can continue to get expanded.

Bug: 177997773
Test: atest inputflinger_tests
Change-Id: If38d395669104d6aebb68f97e830fa80393b50d5