Remove ConnectivityManager swapActiveStatsMap API

swapActiveStatsMap is temporary added for the NetworkStatsFactory to
call BpfNetMaps#swapActiveStatsMap in tethering mainline module. Now
NetworkStatsFactory already be mainlined, calling BpfNetMaps#swapActiveStatsMap
directly.

Bug: 218494448
Test: atest ConnectivityCoverageTests
      atest FrameworksNetTests
Change-Id: I3358e4ac5fb7ed0964273afdbccd1b4128ca7645
diff --git a/service/src/com/android/server/BpfNetMaps.java b/service/src/com/android/server/BpfNetMaps.java
index f2ca18b..f3ac556 100644
--- a/service/src/com/android/server/BpfNetMaps.java
+++ b/service/src/com/android/server/BpfNetMaps.java
@@ -54,6 +54,13 @@
         sInitialized = true;
     }
 
+    /** Constructor used after T that doesn't need to use netd anymore. */
+    public BpfNetMaps() {
+        this(null);
+
+        if (USE_NETD) throw new IllegalArgumentException("BpfNetMaps need to use netd before T");
+    }
+
     public BpfNetMaps(INetd netd) {
         ensureInitialized();
         mNetd = netd;
@@ -247,15 +254,10 @@
     /**
      * Request netd to change the current active network stats map.
      *
-     * @throws RemoteException when netd has crashed.
      * @throws ServiceSpecificException in case of failure, with an error code indicating the
      *                                  cause of the failure.
      */
-    public void swapActiveStatsMap() throws RemoteException {
-        if (USE_NETD) {
-            mNetd.trafficSwapActiveStatsMap();
-            return;
-        }
+    public void swapActiveStatsMap() {
         final int err = native_swapActiveStatsMap();
         maybeThrow(err, "Unable to swap active stats map");
     }