optimize Surface.readFromParcel()

this is called for each relayout() and used to create a full Surface (cpp)
which in turn did some heavy work (including an IPC with surfaceflinger),
most of the time to destroy it immediatelly when the returned surface
(the one in the parcel) was the same.

we now more intelligentely read from the parcel and construct the new
object only if needed.

Change-Id: Idfd40d9ac96ffc6d4ae5fd99bcc0773e131e2267