Revert "Revert "[SurfaceFlinger] Add GPU protected content support.""

This reverts commit 78fb96f3.
Reason for revert: Revert the revert with Fix.

BUG: 35315015
Test: Test with a hacked patch.
Test: Watch Youtube movie, verifed by force GPU composition.
Change-Id: Ic738b5f873dbff322473d4f999074dc35c8813c7