Game Driver: Add SwitchBar to control GUP feature

Uncheck the global switch will hide the preference controllers and force
all apps to use system graphics driver. This change also add a content
observer to notify all the preference controllers of settings global
changes.

Bug: 119221883
Test: make RunSettingsRoboTests
Change-Id: Ice9ded17c759791a3728c552f79881e2215ac081
Merged-In: Ice9ded17c759791a3728c552f79881e2215ac081

src/com/android/settings/development/gup/GameDriverContentObserver.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2019 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.gup;
+
+import android.content.ContentResolver;
+import android.database.ContentObserver;
+import android.os.Handler;
+import android.provider.Settings;
+
+import androidx.annotation.VisibleForTesting;
+
+/**
+ * Helper class to observe Game Driver settings global change.
+ */
+public class GameDriverContentObserver extends ContentObserver {
+    interface OnGameDriverContentChangedListener {
+        void onGameDriverContentChanged();
+    }
+
+    @VisibleForTesting
+    OnGameDriverContentChangedListener mListener;
+
+    public GameDriverContentObserver(Handler handler, OnGameDriverContentChangedListener listener) {
+        super(handler);
+        mListener = listener;
+    }
+
+    @Override
+    public void onChange(boolean selfChange) {
+        super.onChange(selfChange);
+        mListener.onGameDriverContentChanged();
+    }
+
+    public void register(ContentResolver contentResolver) {
+        contentResolver.registerContentObserver(
+                Settings.Global.getUriFor(Settings.Global.GUP_DEV_ALL_APPS), false, this);
+    }
+
+    public void unregister(ContentResolver contentResolver) {
+        contentResolver.unregisterContentObserver(this);
+    }
+}