Revert "remove support for glReadPixels screenshot path"

This reverts commit 3ca76f416bc8665a97636ca8a2d0128b9da9d92c.

Conflicts:
	include/gui/ISurfaceComposer.h
	libs/gui/ISurfaceComposer.cpp
	libs/gui/SurfaceComposerClient.cpp
	services/surfaceflinger/SurfaceFlinger.cpp
	services/surfaceflinger/SurfaceFlinger.h

Change-Id: I8c239e533757af770e418dbb198f5a86c736961f
libgui: Bring back support for mHeap-based screenshots

Older graphics libraries throw a hissy fit when trying to lock
buffers for Surface-based screenshots, on at least Tegra2/3 and
Exynos4 hardware.

This patch depends on the BOARD_USE_MHEAP_SCREENSHOT board flag
and requires the ro.bq.gpu_to_cpu_unsupported property set to 1
in order to work.

[pawitp: port to Lollipop]

Change-Id: I7db955e2cdd120018e349c14290e975788e70ed3

Conflicts:
	services/surfaceflinger/SurfaceFlinger.cpp
	services/surfaceflinger/SurfaceFlinger.h

Conflicts:
	services/surfaceflinger/SurfaceFlinger.cpp
	services/surfaceflinger/SurfaceFlinger.h
Add old getDisplayInfo interface

Needed for TF101 omx
libgui: Add ICS/MR0-compatible client::createSurface constructors

Change-Id: Ia5b04d93320c65ac32a92cbd93daa6a64e6cee1c