In SurfaceFlingerConsumer, check to see if native fence sync is
enabled. If so, defer the texture binding step to Layer::onDraw.
Change-Id: I7d4034a31c0143207eea2509dfa13ef3820f9b8c
Rearranges updateTexImage() so that the SurfaceFlinger-specific
behavior is in a new SurfaceFlingerConsumer subclass.
SurfaceTexture behavior should not be altered. Instead of
acquire-bind-release we now do acquire-release-bind, but since
it's all done with the lock held there shouldn't be any
externally-visible change.
Change-Id: Ia566e4727945e2cfb9359fc6d2a8f8af64d7b7b7