shill: Connect Ethernet Device to DHCPConfig.

Most of the implementation is in the base Device class.

BUG=chromium-os:16794
TEST=unit test

Change-Id: I583761f7e54c88b043ce4343cb43f8298aaedf8b
Reviewed-on: http://gerrit.chromium.org/gerrit/2949
Reviewed-by: Darin Petkov <petkov@chromium.org>
Tested-by: Darin Petkov <petkov@chromium.org>
diff --git a/ipconfig.h b/ipconfig.h
index c29971a..1a10083 100644
--- a/ipconfig.h
+++ b/ipconfig.h
@@ -64,6 +64,8 @@
   void UpdateProperties(const Properties &properties, bool success);
 
  private:
+  FRIEND_TEST(DeviceTest, AcquireDHCPConfig);
+  FRIEND_TEST(DeviceTest, DestroyIPConfig);
   FRIEND_TEST(IPConfigTest, UpdateCallback);
   FRIEND_TEST(IPConfigTest, UpdateProperties);