Add plumbing for HDR metadata

Allow a ANativeWindow client to send HDR metadata to SurfaceFlinger.
The metadata can be queried with
BufferLayerConsumer::getCurrentHdrMetadata.

Written by Courtney.  Updated by olv@.

Bug: 63710530
Test: builds
Change-Id: I23192d4750950664b57863a533bffd72397255b4
14 files changed