hwc: Add support for Secure display

- Identify secure display layer in the hwc_list
- Need to set both SECURE_OVERLAY and SECURE_DISPLAY flags for the secure
  display layer
- Disable idle timeout for secure display usecase, as GPU should not be
  accessing secure display layer

Change-Id: I555910db77c466b5e103b24b4f0ec7f47bb210a5

Conflicts:
	libhwcomposer/hwc_utils.h
gralloc: Fix caching for rarely read/write flags

GRALLOC_USAGE_SW_WRITE_RARELY and GRALLOC_USAGE_SW_READ_RARELY
need to be compared directly since they share bits with
GRALLOC_USAGE_SW_WRITE_OFTEN and GRALLOC_USAGE_SW_READ_OFTEN.

CRs-fixed: 569559

Change-Id: I52692027033e1036e3ad960b9e03dd8ee60b4111
Merge "hwc: Add support for Secure display"
Avoid ov set failures in rapid wfd pause/resume

* Avoid overlay set failures on receiving rapid wfd
pause/resume events.

* Go for videoOnlyComposition when isConfiguring is
set for external/virtual display and secure video
playback is happening instead of falling back to GPU
for composition.

* When external/virtual display is in pause state
and secure playback is happening, go for
videoOnlyComposition instead of full/partial MDP
compostion since the pipes connected to external mixer
will take atleast two vsync cycles to get unset.

* When requesting for an overlay pipe from pipebook,
give preference to the pipe which has already been
allocated to the required LayerMixer in the previous
round.

* Sometimes displayhal receives consecutive wfd-pauses
or wfd-resumes. Add a sanity check to avoid handling
unnecessary wfd pause/resume

Change-Id: Ie0cc835d921f303e1c731c70ae066c375052e5f9
hwc: remove unblanking fb from openframebufferdevice

- unblaking fb is done as part of surface flinger initialization
  so its not required here

Change-Id: Ifaed119503c74b5a75ffd6694d3508c4c15dfb60
Merge "hwc: remove unblanking fb from openframebufferdevice"
Merge "gralloc: Fix caching for rarely read/write flags"
Merge "Avoid ov set failures in rapid wfd pause/resume"
Merge "Merge "Avoid ov set failures in rapid wfd pause/resume""
Merge "Merge "Merge "Avoid ov set failures in rapid wfd pause/resume"""
Merge remote-tracking branch 'ca/kk_2.7.1' into kk-4.4