Build framework-connectivity-tiramisu library

- Move nsd APIs and build framework-connectivity-tiramisu library
- Add nsd associated hidden apis
- Build service-connectivity-tiramisu-pre-jarjar library for
  T+ services.
- Move ConnectivityServiceInitialiizer to service-t directory
  to create S+ service instances which can avoid dependency on
  lower sdk library.

Bug: 206893064
Test: atest FrameworksNetTests CtsNetTestCases
CTS-Coverage-Bug: 207804007
Merged-In: I9628716f5c38047ff4ea2346b27589077259c436
Change-Id: I9628716f5c38047ff4ea2346b27589077259c436

service-t/src/com/android/server/ConnectivityServiceInitializer.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 android.content.Context;
+import android.util.Log;
+
+import com.android.modules.utils.build.SdkLevel;
+
+/**
+ * Connectivity service initializer for core networking. This is called by system server to create
+ * a new instance of ConnectivityService.
+ */
+public final class ConnectivityServiceInitializer extends SystemService {
+    private static final String TAG = ConnectivityServiceInitializer.class.getSimpleName();
+    private final ConnectivityService mConnectivity;
+    private final NsdService mNsdService;
+
+    public ConnectivityServiceInitializer(Context context) {
+        super(context);
+        // Load JNI libraries used by ConnectivityService and its dependencies
+        System.loadLibrary("service-connectivity");
+        mConnectivity = new ConnectivityService(context);
+        mNsdService = createNsdService(context);
+    }
+
+    @Override
+    public void onStart() {
+        Log.i(TAG, "Registering " + Context.CONNECTIVITY_SERVICE);
+        publishBinderService(Context.CONNECTIVITY_SERVICE, mConnectivity,
+                /* allowIsolated= */ false);
+        if (mNsdService != null) {
+            Log.i(TAG, "Registering " + Context.NSD_SERVICE);
+            publishBinderService(Context.NSD_SERVICE, mNsdService, /* allowIsolated= */ false);
+        }
+    }
+
+    /** Return NsdService instance or null if current SDK is lower than T */
+    private NsdService createNsdService(final Context context) {
+        if (!SdkLevel.isAtLeastT()) return null;
+        try {
+            return NsdService.create(context);
+        } catch (InterruptedException e) {
+            Log.d(TAG, "Unable to get NSD service", e);
+            return null;
+        }
+    }
+}