[Settings] init UI entry for Cross SIM calling

Create an empty UI entry for Cross SIM calling.

TODO: fill-in implementation based on UI within document.

Document:
https://docs.google.com/document/d/1INEwrq5_M62hJcRMshdO0OaFruVR0goYByxdpMdFr_o/edit?disco=AAAAHQo7ang&ts=5fadc9b4&usp_dm=true#heading=h.8gw4a7e503pz

Bug: 174012397
Test: manual
Change-Id: I344a18954924c4665295ef244bfee773f3f98d55

tests/unit/src/com/android/settings/network/telephony/CrossSimCallingPreferenceControllerTest.java

@@ -0,0 +1,43 @@
+/*
+ * 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.telephony;
+
+import static org.mockito.Mockito.spy;
+
+import android.content.Context;
+
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+public class CrossSimCallingPreferenceControllerTest {
+    private static final int SUB_ID = 2;
+
+    private CrossSimCallingPreferenceController mController;
+    private Context mContext;
+
+    @Before
+    public void setUp() {
+        mContext = spy(ApplicationProvider.getApplicationContext());
+
+        mController = new CrossSimCallingPreferenceController(mContext, "cross_sim_calling_key");
+        mController.init(SUB_ID);
+    }
+}