Pass a surface to the blit/flip functions, instead of a raw pointer.
This puts the FrameBuffer in control of locking and unlocking.

Change-Id: I55335b3beef8d7083aae7687bd25392964261bde
Reviewed-on: https://swiftshader-review.googlesource.com/4482Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>