Add hidden method to access a connection's service.

This change exposes a method that is used by the actual
fix here: I4e4789c044d9e3614f42143cfa6053881a6d109b

Bug: 17962996
Change-Id: Iec3795ea372634120c71b0a80ee046e372569ecf

telecomm/java/android/telecom/Connection.java

@@ -900,6 +900,13 @@ public abstract class Connection {
         }
     }
 
+    /**
+     * @hide
+     */
+    public final ConnectionService getConnectionService() {
+        return mConnectionService;
+    }
+
     /**
      * Sets the conference that this connection is a part of. This will fail if the connection is
      * already part of a conference call. {@link #resetConference} to un-set the conference first.