Revert "Don't crash Tethering service when WiFi feature is missing"

This reverts commit f6a1052f4e0387b8b95460feb221846d39cf0466.

Reason for revert: Suspected reason for TetheringTests breakage
Bug: 179467044

Change-Id: I3a5ee621b32145b74a31d6c3e411bd789e395935
diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
index ac5857d..385c691 100644
--- a/Tethering/src/com/android/networkstack/tethering/Tethering.java
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -1689,14 +1689,12 @@
             // If this is a Wi-Fi interface, tell WifiManager of any errors
             // or the inactive serving state.
             if (who.interfaceType() == TETHERING_WIFI) {
-                final WifiManager mgr = getWifiManager();
-                final String iface = who.interfaceName();
-                if (mgr == null) {
-                    Log.wtf(TAG, "Skipping WifiManager notification about inactive tethering");
-                } else if (who.lastError() != TETHER_ERROR_NO_ERROR) {
-                    mgr.updateInterfaceIpState(iface, IFACE_IP_MODE_CONFIGURATION_ERROR);
+                if (who.lastError() != TETHER_ERROR_NO_ERROR) {
+                    getWifiManager().updateInterfaceIpState(
+                            who.interfaceName(), IFACE_IP_MODE_CONFIGURATION_ERROR);
                 } else {
-                    mgr.updateInterfaceIpState(iface, IFACE_IP_MODE_UNSPECIFIED);
+                    getWifiManager().updateInterfaceIpState(
+                            who.interfaceName(), IFACE_IP_MODE_UNSPECIFIED);
                 }
             }
         }
@@ -2423,19 +2421,6 @@
             mLog.log(iface + " is not a tetherable iface, ignoring");
             return;
         }
-
-        final PackageManager pm = mContext.getPackageManager();
-        if ((interfaceType == TETHERING_WIFI || interfaceType == TETHERING_WIGIG)
-                && !pm.hasSystemFeature(PackageManager.FEATURE_WIFI)) {
-            mLog.log(iface + " is not tetherable, because WiFi feature is disabled");
-            return;
-        }
-        if (interfaceType == TETHERING_WIFI_P2P
-                && !pm.hasSystemFeature(PackageManager.FEATURE_WIFI_DIRECT)) {
-            mLog.log(iface + " is not tetherable, because WiFi Direct feature is disabled");
-            return;
-        }
-
         maybeTrackNewInterfaceLocked(iface, interfaceType);
     }