Update Mobile Data State on subscription changes.

This CL ensures that Vcn instances refresh their mobile data state
when they receive a new TelephonySubscriptionSnapshot. A new snapshot
may contain different subId -> subGroup mappings, which can affect
whether a Vcn instance's subGroup has mobile data enabled or not. This
in turn can change which VcnGatewayConnections are brought up by the
Vcn.

Bug: 191394092
Test: atest FrameworksVcnTests CtsVcnTestCases
Original-Change: https://android-review.googlesource.com/1740514
Merged-In: Ib59b4ed7900a177b17ed4a6e197e271b10937f65
Change-Id: Ib59b4ed7900a177b17ed4a6e197e271b10937f65

tests/vcn/java/com/android/server/vcn/VcnTest.java

@@ -242,6 +242,27 @@ public class VcnTest {
         verifyUpdateSubscriptionSnapshotNotifiesGatewayConnections(VCN_STATUS_CODE_SAFE_MODE);
     }
 
+    @Test
+    public void testSubscriptionSnapshotUpdatesMobileDataState() {
+        final NetworkRequestListener requestListener = verifyAndGetRequestListener();
+        startVcnGatewayWithCapabilities(requestListener, TEST_CAPS[0]);
+
+        // Expect mobile data enabled from setUp()
+        assertTrue(mVcn.isMobileDataEnabled());
+
+        final TelephonySubscriptionSnapshot updatedSnapshot =
+                mock(TelephonySubscriptionSnapshot.class);
+        doReturn(TEST_SUB_IDS_IN_GROUP)
+                .when(updatedSnapshot)
+                .getAllSubIdsInGroup(eq(TEST_SUB_GROUP));
+        doReturn(false).when(mTelephonyManager).isDataEnabled();
+
+        mVcn.updateSubscriptionSnapshot(updatedSnapshot);
+        mTestLooper.dispatchAll();
+
+        assertFalse(mVcn.isMobileDataEnabled());
+    }
+
     private void triggerVcnRequestListeners(NetworkRequestListener requestListener) {
         for (final int[] caps : TEST_CAPS) {
             startVcnGatewayWithCapabilities(requestListener, caps);