Write Data Saver setting to BPF map

The information is needed by modules who want to know whether a
specific UID is blocked by Data Saver feature.

1. Add a one-element map data_saver_enabled_map.
2. Update current data saver setting to the map.

Bug: 288340533
Test: atest FrameworksNetTests:android.net.connectivity.com.android.serv
er.BpfNetMapsTest
Test: atest bpf_existence_test

Change-Id: I981da4b569247c33cba2d365cb6f2691f673474e
diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index 5ed50ce..dc09237 100755
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -12556,6 +12556,7 @@
         }
     }
 
+    @TargetApi(Build.VERSION_CODES.TIRAMISU)
     @Override
     public void setDataSaverEnabled(final boolean enable) {
         enforceNetworkStackOrSettingsPermission();
@@ -12568,6 +12569,12 @@
             // Lack of permission or binder errors.
             throw new IllegalStateException(e);
         }
+
+        try {
+            mBpfNetMaps.setDataSaverEnabled(enable);
+        } catch (ServiceSpecificException | UnsupportedOperationException e) {
+            Log.e(TAG, "Failed to set data saver " + enable + " : " + e);
+        }
     }
 
     @Override