PreferenceControllers are the way of the future.

Migrates Notification settings (app level, group level, and channel
level) into PreferenceControllers (and most importantly:
PreferenceControllerTest)

Note: this removes the 'Advanced' preference group, but does
not yet use the standard system 'Advanced' grouping as it does
not currently support our use case (where we don't know how many
fields to show outside of 'Advanced' until onResume() and also
where we need fields to show below the 'Advanced' group).

Test: make RunSettingsRoboTests
Change-Id: Iddd1b4771922db322e5f73562e9d63ed077c5396

src/com/android/settings/wrapper/NotificationChannelGroupWrapper.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2017 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.wrapper;
+
+import android.app.NotificationChannelGroup;
+
+/**
+ * Wrapper for {@link NotificationChannelGroup} until roboletric supports O MR1.
+ */
+public class NotificationChannelGroupWrapper {
+
+    private final NotificationChannelGroup mGroup;
+
+    public NotificationChannelGroupWrapper(NotificationChannelGroup group) {
+        mGroup = group;
+    }
+
+    /**
+     * Get the real group object so we can call APIs directly on it.
+     */
+    public NotificationChannelGroup getGroup() {
+        return mGroup;
+    }
+
+    public String getDescription() {
+        if (mGroup != null) {
+            return mGroup.getDescription();
+        }
+        return null;
+    }
+
+    public void setDescription(String desc) {
+        if (mGroup != null) {
+            mGroup.setDescription(desc);
+        }
+    }
+
+    public boolean isBlocked() {
+        if (mGroup != null) {
+            return mGroup.isBlocked();
+        }
+        return true;
+    }
+
+    public void setBlocked(boolean blocked) {
+        if (mGroup != null) {
+            mGroup.setBlocked(blocked);
+        }
+    }
+}