[Provider Model] Add Airplane-safe Networks preference

- Hide the preference when airplane mode is off.

- Reuse PrimarySwitchPreference for RestrictedSwitchPreference

- Screenshot
  https://screenshot.googleplex.com/8HiC5sc8xaqnhz5

Bug: 174022082
Test: atest -c AirplaneSafeNetworksPreferenceControllerTest
Change-Id: I06a56e8e815778cebf200c4a486c414e92f4cb87

src/com/android/settings/network/AirplaneSafeNetworksPreferenceController.java

@@ -0,0 +1,106 @@
+/*
+ * 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.network;
+
+import android.content.Context;
+
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.LifecycleObserver;
+import androidx.lifecycle.OnLifecycleEvent;
+import androidx.preference.PreferenceScreen;
+
+import com.android.settings.AirplaneModeEnabler;
+import com.android.settings.overlay.FeatureFactory;
+import com.android.settings.widget.PrimarySwitchController;
+import com.android.settings.wifi.WifiEnabler;
+import com.android.settingslib.RestrictedSwitchPreference;
+import com.android.settingslib.core.AbstractPreferenceController;
+
+public class AirplaneSafeNetworksPreferenceController extends AbstractPreferenceController
+        implements LifecycleObserver, AirplaneModeEnabler.OnAirplaneModeChangedListener {
+
+    private static final String PREFERENCE_KEY = "airplane_safe_networks";
+
+    private RestrictedSwitchPreference mPreference;
+
+    private AirplaneModeEnabler mAirplaneModeEnabler;
+    private WifiEnabler mWifiEnabler;
+
+    public AirplaneSafeNetworksPreferenceController(Context context, Lifecycle lifecycle) {
+        super(context);
+        if (lifecycle == null) {
+            throw new IllegalArgumentException("Lifecycle must be set");
+        }
+
+        mAirplaneModeEnabler = new AirplaneModeEnabler(mContext, this);
+        lifecycle.addObserver(this);
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return PREFERENCE_KEY;
+    }
+
+    @Override
+    public boolean isAvailable() {
+        return mAirplaneModeEnabler.isAirplaneModeOn();
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+        mPreference = screen.findPreference(getPreferenceKey());
+    }
+
+    @OnLifecycleEvent(Lifecycle.Event.ON_START)
+    public void onStart() {
+        mAirplaneModeEnabler.start();
+        if (mPreference != null) {
+            mWifiEnabler = new WifiEnabler(mContext, new PrimarySwitchController(mPreference),
+                    FeatureFactory.getFactory(mContext).getMetricsFeatureProvider());
+        }
+    }
+
+    @OnLifecycleEvent(Lifecycle.Event.ON_STOP)
+    public void onStop() {
+        mAirplaneModeEnabler.stop();
+        if (mWifiEnabler != null) {
+            mWifiEnabler.teardownSwitchController();
+        }
+    }
+
+    @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
+    public void onResume() {
+        if (mWifiEnabler != null) {
+            mWifiEnabler.resume(mContext);
+        }
+    }
+
+    @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
+    public void onPause() {
+        if (mWifiEnabler != null) {
+            mWifiEnabler.pause();
+        }
+    }
+
+    @Override
+    public void onAirplaneModeChanged(boolean isAirplaneModeOn) {
+        if (mPreference != null) {
+            mPreference.setVisible(isAirplaneModeOn);
+        }
+    }
+}

src/com/android/settings/network/NetworkDashboardFragment.java

@@ -147,6 +147,7 @@ public class NetworkDashboardFragment extends DashboardFragment implements
         controllers.add(privateDnsPreferenceController);
         if (Utils.isProviderModelEnabled(context)) {
             controllers.add(new NetworkProviderCallsSmsController(context, lifecycle));
+            controllers.add(new AirplaneSafeNetworksPreferenceController(context, lifecycle));
         }
         return controllers;
     }