Add NetworkProvider to VcnManagementService

This change adds a skeleton VcnNetworkProvider, and registers it with
ConnectivityService upon system startup.

Bug: 163431879
Test: FrameworksVcnTests passing
Change-Id: I7720db1cea805cbdca052a2e37cb2d754189ea05

tests/vcn/java/com/android/server/VcnManagementServiceTest.java

@@ -0,0 +1,62 @@
+/*
+ * 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.server;
+
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import android.content.Context;
+import android.net.ConnectivityManager;
+import android.os.test.TestLooper;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Tests for {@link VcnManagementService}. */
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class VcnManagementServiceTest {
+    private final Context mMockContext = mock(Context.class);
+    private final VcnManagementService.Dependencies mMockDeps =
+            mock(VcnManagementService.Dependencies.class);
+    private final TestLooper mTestLooper = new TestLooper();
+    private final ConnectivityManager mConnMgr = mock(ConnectivityManager.class);
+    private final VcnManagementService mVcnMgmtSvc;
+
+    public VcnManagementServiceTest() {
+        doReturn(Context.CONNECTIVITY_SERVICE)
+                .when(mMockContext)
+                .getSystemServiceName(ConnectivityManager.class);
+        doReturn(mConnMgr).when(mMockContext).getSystemService(Context.CONNECTIVITY_SERVICE);
+
+        doReturn(mTestLooper.getLooper()).when(mMockDeps).getLooper();
+        mVcnMgmtSvc = new VcnManagementService(mMockContext, mMockDeps);
+    }
+
+    @Test
+    public void testSystemReady() throws Exception {
+        mVcnMgmtSvc.systemReady();
+
+        verify(mConnMgr)
+                .registerNetworkProvider(any(VcnManagementService.VcnNetworkProvider.class));
+    }
+}