Add a Preference into "Network & internet" for new tethering UI

Adding a MasterSwitchPreference into "Network & internet" and create
corresponding controller. The preference is hidden by the feature flag.
It does NOT affect the existing UI.

Bug: 146147778
Test: CodeInspectionTest, TetherPreferenceControllerTest,
NetworkDashboardFragmentTest
Change-Id: Ida8e088efbb22d0c983acecbc420672206392dad

tests/robotests/src/com/android/settings/network/AllInOneTetherPreferenceControllerTest.java

@@ -0,0 +1,93 @@
+/*
+ * 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 static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothPan;
+import android.bluetooth.BluetoothProfile;
+import android.content.Context;
+
+import com.android.settings.widget.MasterSwitchPreference;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.util.ReflectionHelpers;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+@RunWith(RobolectricTestRunner.class)
+public class AllInOneTetherPreferenceControllerTest {
+
+    @Mock
+    private Context mContext;
+    @Mock
+    private BluetoothAdapter mBluetoothAdapter;
+    @Mock
+    private MasterSwitchPreference mPreference;
+
+    private AllInOneTetherPreferenceController mController;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mController = spy(AllInOneTetherPreferenceController.class);
+        ReflectionHelpers.setField(mController, "mContext", mContext);
+        ReflectionHelpers.setField(mController, "mBluetoothAdapter", mBluetoothAdapter);
+        ReflectionHelpers.setField(mController, "mPreference", mPreference);
+    }
+
+    @Test
+    public void lifeCycle_onCreate_shouldInitBluetoothPan() {
+        when(mBluetoothAdapter.getState()).thenReturn(BluetoothAdapter.STATE_ON);
+        mController.onCreate();
+
+        verify(mBluetoothAdapter).getState();
+        verify(mBluetoothAdapter).getProfileProxy(mContext, mController.mBtProfileServiceListener,
+                BluetoothProfile.PAN);
+    }
+
+    @Test
+    public void lifeCycle_onCreate_shouldNotInitBluetoothPanWhenBluetoothOff() {
+        when(mBluetoothAdapter.getState()).thenReturn(BluetoothAdapter.STATE_OFF);
+        mController.onCreate();
+
+        verify(mBluetoothAdapter).getState();
+        verifyNoMoreInteractions(mBluetoothAdapter);
+    }
+
+    @Test
+    public void goThroughLifecycle_shouldDestroyBluetoothProfile() {
+        final BluetoothPan pan = mock(BluetoothPan.class);
+        final AtomicReference<BluetoothPan> panRef =
+                ReflectionHelpers.getField(mController, "mBluetoothPan");
+        panRef.set(pan);
+
+        mController.onDestroy();
+
+        verify(mBluetoothAdapter).closeProfileProxy(BluetoothProfile.PAN, pan);
+    }
+}