Merge "Remove non-A/B mention from README."

# SystemUpdaterSample

This app demonstrates how to use Android system updates APIs to install

[OTA updates](https://source.android.com/devices/tech/ota/). It contains a sample

client for `update_engine` to install A/B (seamless) updates and a sample of

applying non-A/B updates using `recovery`.

[OTA updates](https://source.android.com/devices/tech/ota/). It contains a

sample client for `update_engine` to install A/B (seamless) updates.

A/B (seamless) update is available since Android Nougat (API 24), but this sample

targets the latest android.

`update_engine` service as well as OTA package files. Detailed steps are as follows:

1. [Prepare to build](https://source.android.com/setup/build/building)

2. Add the module (SystemUpdaterSample) to the `PRODUCT_PACKAGES` list for the lunch target.

2. Add the module (SystemUpdaterSample) to the `PRODUCT_PACKAGES` list for the

   lunch target.

   e.g. add a line containing `PRODUCT_PACKAGES += SystemUpdaterSample`

   to `device/google/marlin/device-common.mk`.

3. [Whitelist the sample app](https://source.android.com/devices/tech/config/perms-whitelist)

- [x] Add smart update completion detection using onStatusUpdate

- [x] Add pause/resume demo

- [ ] Verify system partition checksum for package

- [?] Add non-A/B updates demo

## Running tests

## Accessing `android.os.UpdateEngine` API

`android.os.UpdateEngine`` APIs are marked as `@SystemApi`, meaning only system apps can access them.

`android.os.UpdateEngine` APIs are marked as `@SystemApi`, meaning only system

apps can access them.

## Getting read/write access to `/data/ota_package/`