Migrate screenshot methods to AIDL

A new service, SurfaceFlingerAIDL, is added to surfaceflinger during
the process of mirgrating ISurfaceComposer interface to AIDL.
Once migration is complete, this service will be deleted.

Bug: 211037638
Test: screencap

Change-Id: I0e41700b1af1f482cda6a6d6c67b057553485cfd
1 file changed