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

src/com/android/settings/development/transcode/TranscodeGlobalTogglePreferenceController.java

@@ -0,0 +1,52 @@
+/*
+ * 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.
+ */
+
+package com.android.settings.development.transcode;
+
+import android.content.Context;
+import android.os.SystemProperties;
+
+import com.android.settings.core.TogglePreferenceController;
+
+/**
+ * The controller for the "Enable transcode for all apps" switch on the transcode settings
+ * screen.
+ */
+public class TranscodeGlobalTogglePreferenceController extends TogglePreferenceController {
+
+    private static final String TRANSCODE_ENABLED_PROP_KEY = "persist.sys.fuse.transcode";
+
+    public TranscodeGlobalTogglePreferenceController(Context context,
+            String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+
+    @Override
+    public boolean isChecked() {
+        return SystemProperties.getBoolean(TRANSCODE_ENABLED_PROP_KEY, false);
+    }
+
+    @Override
+    public boolean setChecked(boolean isChecked) {
+        SystemProperties.set(TRANSCODE_ENABLED_PROP_KEY, String.valueOf(isChecked));
+        return true;
+    }
+}