New feature “Text and reading options” for SetupWizard, Wallpaper, and Settings (6/n).

- Create new preview preference.
1) It will be integrated with TextReadingPreferenceFragment, and sub
previews layouts like app launchers, conversation messages, and mail
content.

Bug: 211503117
Test: make -j64 RunSettingsRoboTests ROBOTEST_FILTER=TextReadingPreviewPreferenceTest
Change-Id: I2d82d58438ee3f96c5a8dbb1809a0d6bdf3a00a2

res/drawable/accessibility_text_reading_preview.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Copyright (C) 2022 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.
+-->
+
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:androidprv="http://schemas.android.com/apk/prv/res/android"
+    android:shape="rectangle">
+
+    <corners android:radius="28dp" />
+    <solid android:color="?androidprv:attr/colorSurface" />
+</shape>