Make VpnService synchronous API.

This eases VpnSettings on dealing with multiple-activity-instance problem
(i.e., SettingsActivity and VpnSettingsActivity).

+ Most of the code is moved from the VpnServices package to vpn/java/.
+ VpnManager and VpnServiceBinder are revised to provide synchronous API.
+ Add a new method isIdle() to IVpnService.aidl.

Related bug: 3293236 (need to deal with multiple-activity-instance problem)

Change-Id: I03afa3b3af85d7b4ef800683cd075c356a9266c4

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

@@ -32,6 +32,7 @@ import android.net.NetworkStateTracker;
 import android.net.NetworkUtils;
 import android.net.Proxy;
 import android.net.ProxyProperties;
+import android.net.vpn.VpnManager;
 import android.net.wifi.WifiStateTracker;
 import android.os.Binder;
 import android.os.Handler;
@@ -442,6 +443,8 @@ public class ConnectivityService extends IConnectivityManager.Stub {
         mSettingsObserver.observe(mContext);
 
         loadGlobalProxy();
+
+        VpnManager.startVpnService(context);
     }