sample_updater: add non-streaming demo

SampleUpdater app was tested manually on a device.
There are unit tests for utility classes.

SampleUpdater app demonstrates how to use Android Update Engine to
apply A/B (seamless) update.
This CL contains demo of non-stream update using async update_engine,
which is accessed directly from an activity.
This app also shows logs from update_engine on the UI.
Instructions can be found in `README.md`.

- Create a UI with list of configs, current version, control buttons and a progress bar
- Add PayloadSpec and PayloadSpecs for working with update zip file
- Add UpdateConfig for working with json config files
- Add applying non-streaming update

Test: tested manually and unit tests for utilities
Change-Id: I05d4a46ad9cf8b334c9c60c7dd4da486dac0400a
Signed-off-by: Zhomart Mukhamejanov <zhomart@google.com>
diff --git a/sample_updater/res/values/strings.xml b/sample_updater/res/values/strings.xml
new file mode 100644
index 0000000..2b671ee
--- /dev/null
+++ b/sample_updater/res/values/strings.xml
@@ -0,0 +1,21 @@
+<!-- Copyright (C) 2018 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+<resources>
+    <string name="app_name">SystemUpdaterSample</string>
+    <string name="action_reload">Reload</string>
+    <string name="unknown">Unknown</string>
+    <string name="close">CLOSE</string>
+</resources>