Add Transcode Settings screen in Developer Options

This screen would be used to enable/disable transcoding for all apps, and select a list of apps to be skipped from transcoding.
UI screenshot: https://screenshot.googleplex.com/4bpbZdM6vbhdw5u

Design doc reference for native transcoding: go/seamless-transcoding

Test: Manual
Bug: 169547037
Change-Id: I7cf72131560b99728083838bf0dad400bb5cb4a9

res/xml/transcode_settings.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2020 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.
+  -->
+
+<PreferenceScreen
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:settings="http://schemas.android.com/apk/res-auto"
+    android:title="@string/transcode_settings_title"
+    settings:searchable="false">
+
+    <SwitchPreference
+        android:key="transcode_enable_all"
+        android:title="@string/transcode_enable_all"
+        settings:controller="com.android.settings.development.transcode.TranscodeGlobalTogglePreferenceController" />
+
+    <PreferenceCategory
+        android:key="transcode_skip_apps"
+        android:title="@string/transcode_skip_apps"
+        settings:controller="com.android.settings.development.transcode.TranscodeSkipAppsPreferenceController" />
+</PreferenceScreen>