Revert "Revert "Block incoming non-VPN packets to apps under fully-routed VPN""

This reverts commit 3897df2e36d4d015304b398c545c1232ee35a1c9.

Reason for revert: Rolling forward, will fix tests in same CL stack.

Bug: 114231106
Bug: 130397860
Test: FrameworksNetTests
Change-Id: Ia8a0c99b4e1fd5dff26c881715cd876618ca4321
diff --git a/core/java/android/net/NetworkCapabilities.java b/core/java/android/net/NetworkCapabilities.java
index 99375f8..dfd7089 100644
--- a/core/java/android/net/NetworkCapabilities.java
+++ b/core/java/android/net/NetworkCapabilities.java
@@ -822,6 +822,11 @@
         mEstablishingVpnAppUid = uid;
     }
 
+    /** @hide */
+    public int getEstablishingVpnAppUid() {
+        return mEstablishingVpnAppUid;
+    }
+
     /**
      * Value indicating that link bandwidth is unspecified.
      * @hide