shill: Add unit tests for RTNLListener.

BUG=chromium-os:17394
TEST=unit tests

Change-Id: I2b68d24d14ff11c9c071c4321790a9214e7d7997
Reviewed-on: http://gerrit.chromium.org/gerrit/3819
Reviewed-by: Darin Petkov <petkov@chromium.org>
Tested-by: Darin Petkov <petkov@chromium.org>
diff --git a/rtnl_listener.h b/rtnl_listener.h
index 4fff5a2..c606527 100644
--- a/rtnl_listener.h
+++ b/rtnl_listener.h
@@ -15,10 +15,13 @@
  public:
   RTNLListener(int listen_flags, Callback1<struct nlmsghdr *>::Type *callback);
   ~RTNLListener();
+
   void NotifyEvent(int type, struct nlmsghdr *hdr);
+
  private:
   int listen_flags_;
   Callback1<struct nlmsghdr *>::Type *callback_;
+
   DISALLOW_COPY_AND_ASSIGN(RTNLListener);
 };