Add UID and directory for RELRO sharing support.

Define a UID to be used by the process responsible for creating shared
RELRO files for the WebView native library, and create a directory owned
by that UID to use to store the files.

Bug: 13005501
Change-Id: I5bbb1e1035405e5534b2681f554fe16f74e3da1a
2 files changed