Fix switch bar in location settings

When user rotates the device in location settings, the swtich bar with
"Use Location" is gone. This change fixes the problem.

Also, remove override getInitialExpandedChildCount() in
LocationSettings. We will use nested PreferenceCategory instead once the
support is ready.

Bug: 73872033
Bug: 70843646
Test: Manual
Change-Id: I343b549398ef2b3d64ca7962b5f2a4ef0441c7f5

tests/robotests/src/com/android/settings/location/LocationSettingsTest.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2018 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.location;
+
+import android.os.Bundle;
+import com.android.settings.SettingsActivity;
+import com.android.settings.TestConfig;
+import com.android.settings.testutils.SettingsRobolectricTestRunner;
+import com.android.settings.widget.SwitchBar;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.annotation.Config;
+
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+
+@RunWith(SettingsRobolectricTestRunner.class)
+@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
+public class LocationSettingsTest {
+
+    @Mock
+    private SettingsActivity mActivity;
+    @Mock
+    private SwitchBar mSwitchBar;
+
+    private LocationSettings mLocationSettings;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mLocationSettings = spy(new LocationSettings());
+        doReturn(mActivity).when(mLocationSettings).getActivity();
+        doReturn(mSwitchBar).when(mActivity).getSwitchBar();
+    }
+
+    @Test
+    public void onActivityCreated_shouldShowSwitchBar() {
+        mLocationSettings.onActivityCreated(new Bundle());
+
+        verify(mSwitchBar).show();
+    }
+}