Request focus using setFocusedWindow

This change introduces two new SurfaceControl apis, one to request focus
to a particular window and the other to transfer focus to an embedded
window if the host window is currently focused.

WindowHandleInfo is updated to specify focusability instead of the
currently focused window. This will provide more information to
InputDipatcher on what all the focusable windows are on screen and
in the future allow it to determine a new focus target.

Lastly, after updating all the WindowHandles in InputMonitor, we switch
over to calling setFocusedWindow to specify the desired focused window.
There should be no functional changes with this cl.

Test: atest inputflinger_tests
Test: atest CtsWindowManagerDeviceTestCases
Test: atest FlickerTests

Bug: 151179149
Change-Id: Iefda51ce73247b208115e64f9f8159a182d93ded