Merge changes from topic "readonly_generic_ramdisk" am: 696882455b am: 3401909e7c am: 6c9f509cdb

Original change: https://android-review.googlesource.com/c/platform/system/core/+/1519823

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I19c9b5e3aff01395f4446b00828ac419716180b8