Revert "remove support for glReadPixels screenshot path"

This reverts commit 3ca76f416bc8665a97636ca8a2d0128b9da9d92c.

Change-Id: I481fdd5ac4b37853862c1f243fdf31ce73d53e37
Merge "Revert "remove support for glReadPixels screenshot path"" into android-4.4