commit 44addfe5d29023045784293459fab78a5899863b
author Jiwen 'Steve' Cai <jwcai@google.com> Tue Mar 13 21:37:11 2018 -0700
committer Jiwen 'Steve' Cai <jwcai@google.com> Mon Apr 02 15:43:41 2018 -0700
tree d43fe13b0792cdc95e89ed85864fa724eef9c1af
parent 781a6f09d9b0bc212842aee67c86b79cf2593e69

GraphicBuffer: add optional DetachedBufferHandle

Stores a BufferHub handle that can be used to reattach this
GraphicBuffer back into a BufferHub producer/consumer set. In terms of
GraphicBuffer's relationship with BufferHub, there are three different
modes:

1. Legacy mode: GraphicBuffer is not backed by BufferHub and
   mDetachedBufferHandle must be invalid.
2. Detached mode: GraphicBuffer is backed BufferHub, but not part of a
   producer/consumer set. In this mode, mDetachedBufferHandle must be valid.
3. Attached mode: GraphicBuffer is backed BufferHub and it's part of a
   producer/consumer set. In this mode, mDetachedBufferHandle must be
   invalid.

Note that the DetachedBufferHandle is used as a opaque handle for
GraphicBuffer and it's not exposed to VNDK.

Bug: 38137191
Bug: 69982239
Bug: 70046255
Bug: 70912269
Test: GraphicBuffer_test
Change-Id: I4c3a967cb498291aa175312fdadc84edd3b1a8be