Add flag to reset notification channel importance

Add a button in development option to unlock user previously changed
notification importance and allow NAS to change the importance

Test: make RunSettingsRoboTests
Change-Id: I55b5349d6a17a383888c59b9126832c2fb8c58a0

src/com/android/settings/notification/ImportanceResetPreferenceController.java

@@ -0,0 +1,68 @@
+/*
+ * 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.notification;
+
+import android.content.Context;
+import android.view.View;
+import android.widget.Button;
+
+import androidx.preference.Preference;
+
+import com.android.settings.R;
+import com.android.settings.core.BasePreferenceController;
+import com.android.settingslib.widget.LayoutPreference;
+
+public class ImportanceResetPreferenceController extends BasePreferenceController implements
+        View.OnClickListener {
+
+    public static final String KEY = "asst_importance_reset";
+    private static final String TAG = "ResetImportanceButton";
+
+    private NotificationBackend mBackend;
+    private Button mButton;
+
+    public ImportanceResetPreferenceController(Context context, String key) {
+        super(context, key);
+        mBackend = new NotificationBackend();
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return KEY;
+    }
+
+    @Override
+    public void updateState(Preference preference) {
+        super.updateState(preference);
+
+        mButton = ((LayoutPreference) preference)
+                .findViewById(R.id.reset_importance_button);
+        mButton.setOnClickListener(this);
+    }
+
+    @Override
+    public void onClick(View v) {
+        mBackend.resetNotificationImportance();
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+
+}
+