Derestrict mSurfaceTexture, mProducer.

Usage has been discovered by an app so reverting this to its previous
state. This is conceptually a partial revert of change 5d123b67.

NoNonSdkCheck: b/170729553

Bug: 176388660
Test: m
Change-Id: I4399e4d431f8a443343de312e131fbf86d0f60b5