Cosmetic: Add a way to query the type of a network.

This is a cosmetic change, i.e., there's no change in functionality.

This is the poor man's RTTI. It turns out that maintaining separate lists (or
maps) of the different types of networks gets burdensome pretty quickly
(especially in an upcoming CL where we add functions like
canUserSelectNetwork()).

Change-Id: If5250c0fc106045f681d0fd71278b793addbe1e3
diff --git a/server/NetworkController.h b/server/NetworkController.h
index cc6e953..1968ab5 100644
--- a/server/NetworkController.h
+++ b/server/NetworkController.h
@@ -28,9 +28,7 @@
 #include <vector>
 
 class Network;
-class PhysicalNetwork;
 class UidRanges;
-class VirtualNetwork;
 
 /*
  * Keeps track of default, per-pid, and per-uid-range network selection, as
@@ -94,12 +92,11 @@
         UidEntry(uid_t uidStart, uid_t uidEnd, unsigned netId, bool forwardDns);
     };
 
-    // mRWLock guards all accesses to mUidMap, mDefaultNetId, mPhysicalNetworks and mUsers.
+    // mRWLock guards all accesses to mUidMap, mDefaultNetId, mNetworks and mUsers.
     mutable android::RWLock mRWLock;
     std::list<UidEntry> mUidMap;
     unsigned mDefaultNetId;
-    std::map<unsigned, PhysicalNetwork*> mPhysicalNetworks;  // Map keys are NetIds.
-    std::map<unsigned, VirtualNetwork*> mVirtualNetworks;  // Map keys are NetIds.
+    std::map<unsigned, Network*> mNetworks;  // Map keys are NetIds.
     std::map<uid_t, Permission> mUsers;
 };