Camera: Add hidden camera preview to renderscript allocation API

- Camera.createPreviewAllocation() creates YUV allocations for use as
  a preview buffer destination.

- Camera.setPreviewCallbackAllocation() sets such an allocation as the
  target for preview data from camera.

Bug: 8563840
Change-Id: Ie42033976fed825d396550bbc033d434c8206b6b
2 files changed