Merge "Allow hal_graphics_composer to write to a pipe      We would like SurfaceFlinger to be able to create a pipe and provide the write-end to the graphics composer to dump debug info for dumpsys.       Bug: 220171623  Test: atest VtsHalGraphicsComposer3_TargetTest  Test: adb shell dumpsys SurfaceFlinger  Test: adb shell dumpsys android.hardware.graphics.composer3.IComposer/default"