[IT03] Add replacement methods for network activity

Reference for NMS in ConnectivityManager should be removed for
incoming CS mainline. The API for listening network activity
should not go into NMS. As an alternative, the registry requests
should be sent to CS and handled by CS. Add necessary alternative
in IConnectivityManger first. The detail implementation will be
added in the follow up commits.

Bug: 170598012
Test: m
Change-Id: If4d24b937feb88a61f22073af2f671cf20298364

core/java/android/net/IConnectivityManager.aidl

@@ -31,6 +31,7 @@ import android.net.ISocketKeepaliveCallback;
 import android.net.ProxyInfo;
 import android.os.Bundle;
 import android.os.IBinder;
+import android.os.INetworkActivityListener;
 import android.os.Messenger;
 import android.os.ParcelFileDescriptor;
 import android.os.PersistableBundle;
@@ -233,4 +234,10 @@ interface IConnectivityManager
                 in PersistableBundle extras);
 
     void systemReady();
+
+    void registerNetworkActivityListener(in INetworkActivityListener l);
+
+    void unregisterNetworkActivityListener(in INetworkActivityListener l);
+
+    boolean isDefaultNetworkActive();
 }

services/core/java/com/android/server/ConnectivityService.java

@@ -146,6 +146,7 @@ import android.os.Bundle;
 import android.os.Handler;
 import android.os.HandlerThread;
 import android.os.IBinder;
+import android.os.INetworkActivityListener;
 import android.os.INetworkManagementService;
 import android.os.Looper;
 import android.os.Message;
@@ -2339,6 +2340,31 @@ public class ConnectivityService extends IConnectivityManager.Stub
         mHandler.sendMessage(mHandler.obtainMessage(EVENT_SYSTEM_READY));
     }
 
+    /**
+     * Start listening for default data network activity state changes.
+     */
+    @Override
+    public void registerNetworkActivityListener(@NonNull INetworkActivityListener l) {
+        // TODO: Replace network activity listener registry in ConnectivityManager from NMS to here
+    }
+
+    /**
+     * Stop listening for default data network activity state changes.
+     */
+    @Override
+    public void unregisterNetworkActivityListener(@NonNull INetworkActivityListener l) {
+        // TODO: Replace network activity listener registry in ConnectivityManager from NMS to here
+    }
+
+    /**
+     * Check whether the default network radio is currently active.
+     */
+    @Override
+    public boolean isDefaultNetworkActive() {
+        // TODO: Replace isNetworkActive() in NMS.
+        return false;
+    }
+
     /**
      * Setup data activity tracking for the given network.
      *