Minor fixes to LockdownVpnTracker.

1. Remove the legacy network type. This is only used for logging.
   - Replace the logcat logging with the display transport
   - Remove the EventLogTags logging, since it's likely not
     actually used by anyone.

2. Remove code that checks for NetworkInfo objects in state
   FAILED, since LockdownVpnTracker can never have received any
   such NetworkInfo from ConnectivityService since lollipop.

Bug: 173331190
Test: passes existing tests in ConnectivityServiceTest
Change-Id: I66ed71e51ba18b95862f3a0a5df2775eecea501e

services/core/java/com/android/server/ConnectivityService.java

@@ -746,7 +746,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
                         + Arrays.toString(vpnNai.declaredUnderlyingNetworks));
                 return;
             }
-            final NetworkAgentInfo underlyingNai =  mService.getNetworkAgentInfoForNetwork(
+            final NetworkAgentInfo underlyingNai = mService.getNetworkAgentInfoForNetwork(
                     vpnNai.declaredUnderlyingNetworks[0]);
             if (underlyingNai == null) return;
 
@@ -4824,12 +4824,15 @@ public class ConnectivityService extends IConnectivityManager.Stub
         if (!mLockdownEnabled) {
             return null;
         }
-        // The legacy lockdown VPN always only applies to UID 0.
+        // The legacy lockdown VPN always only applies to userId 0.
         final NetworkAgentInfo nai = getVpnForUid(Process.FIRST_APPLICATION_UID);
         if (nai == null || !isLegacyLockdownNai(nai)) return null;
 
         // The legacy lockdown VPN must always have exactly one underlying network.
-        if (nai.declaredUnderlyingNetworks == null ||  nai.declaredUnderlyingNetworks.length != 1) {
+        // This code may run on any thread and declaredUnderlyingNetworks may change, so store it in
+        // a local variable. There is no need to make a copy because its contents cannot change.
+        final Network[] underlying = nai.declaredUnderlyingNetworks;
+        if (underlying == null ||  underlying.length != 1) {
             return null;
         }
 
@@ -4839,8 +4842,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
         // Report that the VPN is not connected, so when the state of NetworkInfo objects
         // overwritten by getLegacyLockdownState will be set to CONNECTING and not CONNECTED.
         final NetworkAgentInfo defaultNetwork = getDefaultNetwork();
-        if (defaultNetwork == null
-                || !defaultNetwork.network.equals(nai.declaredUnderlyingNetworks[0])) {
+        if (defaultNetwork == null || !defaultNetwork.network.equals(underlying[0])) {
             return null;
         }
 
@@ -4899,6 +4901,9 @@ public class ConnectivityService extends IConnectivityManager.Stub
     private BroadcastReceiver mIntentReceiver = new BroadcastReceiver() {
         @Override
         public void onReceive(Context context, Intent intent) {
+            // TODO: make BroadcastInterceptingContext use the Handler passed in to registerReceiver
+            // and put this back.
+            // ensureRunningOnConnectivityServiceThread();
             final String action = intent.getAction();
             final int userId = intent.getIntExtra(Intent.EXTRA_USER_HANDLE, UserHandle.USER_NULL);