The event log tag service uses /dev/event-log-tags, pstore and
/data/misc/logd/event-log-tags as sticky storage for the invented
log tags.

Test: gTest liblog-unit-tests, logd-unit-tests & logcat-unit-tests
Bug: 31456426
Change-Id: Iacc8f36f4a716d4da8dca78a4a54600ad2a288dd

Create an event_log_tags_file label and use it for
/dev/event-log-tags.  Only trusted system log readers are allowed
direct read access to this file, no write access.  Untrusted domain
requests lack direct access, and are thus checked for credentials via
the "plan b" long path socket to the event log tag service.

Test: gTest logd-unit-tests, liblog-unit-tests and logcat-unit-tests
Bug: 31456426
Bug: 30566487
Change-Id: Ib9b71ca225d4436d764c9bc340ff7b1c9c252a9e

- transition to logpersist from init
- sort some overlapping negative references
- intention is to allow logpersist to be used by vendor
  userdebug logging

Test: gTest liblog-unit-tests, logd-unit-tests & logcat-unit-tests
Bug: 30566487
Change-Id: I7806f5a2548cbe0c1f257a0ba2855f2eb69d8e7c

In order to support platform changes without simultaneous updates from
non-platform components, the platform and non-platform policies must be
split.  In order to provide a guarantee that policy written for
non-platform objects continues to provide the same access, all types
exposed to non-platform policy are versioned by converting them and the
policy using them into attributes.

This change performs that split, the subsequent versioning and also
generates a mapping file to glue the different policy components
together.

Test: Device boots and runs.
Bug: 31369363
Change-Id: Ibfd3eb077bd9b8e2ff3b2e6a0ca87e44d78b1317

Divide policy into public and private components.  This is the first
step in splitting the policy creation for platform and non-platform
policies.  The policy in the public directory will be exported for use
in non-platform policy creation.  Backwards compatibility with it will
be achieved by converting the exported policy into attribute-based
policy when included as part of the non-platform policy and a mapping
file will be maintained to be included with the platform policy that
maps exported attributes of previous versions to the current platform
version.

Eventually we would like to create a clear interface between the
platform and non-platform device components so that the exported policy,
and the need for attributes is minimal.  For now, almost all types and
avrules are left in public.

Test: Tested by building policy and running on device.

Change-Id: Idef796c9ec169259787c3f9d8f423edf4ce27f8c