Add SystemApi for captive portal metrics

The metrics go through NetworkMonitor in the NetworkStack so that they
can be upgraded to new metrics in the future.

Test: flashed, captive portal login works, metrics shown in events log
Bug: 112869080
(Cherry-pick of aosp/890004)

Change-Id: I4bccfbd87bae5b2d65e45c7a5918aa45ab5d76e8
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 1519c17..a5cdf37 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -144,6 +144,7 @@
 import com.android.internal.annotations.GuardedBy;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.app.IBatteryStats;
+import com.android.internal.logging.MetricsLogger;
 import com.android.internal.net.LegacyVpnInfo;
 import com.android.internal.net.VpnConfig;
 import com.android.internal.net.VpnInfo;
@@ -2683,6 +2684,11 @@
                     EVENT_PROVISIONING_NOTIFICATION, PROVISIONING_NOTIFICATION_HIDE,
                     mNai.network.netId));
         }
+
+        @Override
+        public void logCaptivePortalLoginEvent(int eventId, String packageName) {
+            new MetricsLogger().action(eventId, packageName);
+        }
     }
 
     private boolean networkRequiresValidation(NetworkAgentInfo nai) {