Tell the system when tethering offload hits a limit.

Add a new tetherLimitReached method to INetworkManagementService,
and call it when the HAL notifies OffloadController because the
limit has been reached.

Bug: 29337859
Bug: 32163131
Test: builds
Test: OffloadControllerTest passes

(cherry picked from commit d66cf56ba662f10f2da1d0f844116632ad0a0dbb)

Change-Id: I89719fe7ec8bfd3c85d6cdca9c0d449aea86ef9d
Merged-In: I026e6aa9e7b371f316c0d97c3cf5e78abc1f5263
diff --git a/services/core/java/com/android/server/NetworkManagementService.java b/services/core/java/com/android/server/NetworkManagementService.java
index 3d638be..51e2a70 100644
--- a/services/core/java/com/android/server/NetworkManagementService.java
+++ b/services/core/java/com/android/server/NetworkManagementService.java
@@ -529,6 +529,18 @@
         }
     }
 
+    @Override
+    public void tetherLimitReached(ITetheringStatsProvider provider) {
+        mContext.enforceCallingOrSelfPermission(NETWORK_STACK, TAG);
+        synchronized(mTetheringStatsProviders) {
+            if (!mTetheringStatsProviders.containsKey(provider)) {
+                return;
+            }
+            // No current code examines the interface parameter in a global alert. Just pass null.
+            notifyLimitReached(LIMIT_GLOBAL_ALERT, null);
+        }
+    }
+
     // Sync the state of the given chain with the native daemon.
     private void syncFirewallChainLocked(int chain, SparseIntArray uidFirewallRules, String name) {
         int size = uidFirewallRules.size();