Clean up APN notifications.

Add APNType info to notifications so you can tell what's happening.  Now, even if a new APN
shares a connection with an already-connected-to- apn type, the new type will get all
the connecting and connected messages on connect and disconnecting/disconnected on disconnect
even though the shared connection remains connected.

Cleaning out the hacks MobileDataStateTracker needed to deal with the old situation.
bug:2226092

Change-Id: Iddd7421d6b91cda7c8405f9c3d5404ac04ef8e42

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

@@ -597,15 +597,7 @@ public class ConnectivityService extends IConnectivityManager.Stub {
                 network.reconnect();
                 return Phone.APN_REQUEST_STARTED;
             } else {
-                synchronized(this) {
-                    mFeatureUsers.add(f);
-                }
-                mHandler.sendMessageDelayed(mHandler.obtainMessage(
-                        NetworkStateTracker.EVENT_RESTORE_DEFAULT_NETWORK,
-                        f), getRestoreDefaultNetworkDelay());
-
-                return network.startUsingNetworkFeature(feature,
-                        getCallingPid(), getCallingUid());
+                return -1;
             }
         }
         return Phone.APN_TYPE_NOT_AVAILABLE;
@@ -724,8 +716,7 @@ public class ConnectivityService extends IConnectivityManager.Stub {
             tracker.teardown();
             return 1;
         } else {
-            // do it the old fashioned way
-            return tracker.stopUsingNetworkFeature(feature, pid, uid);
+            return -1;
         }
     }