[shill] Start replacing bare pointers with scoped_refptrs where appropriate

BUG=chromium-os:16259
TEST=unit tests

Change-Id: I5e1531b726bbb40917d25dc3ae44da9a6a420e00
Reviewed-on: http://gerrit.chromium.org/gerrit/2236
Tested-by: Chris Masone <cmasone@chromium.org>
Reviewed-by: Darin Petkov <petkov@chromium.org>
diff --git a/ipconfig.cc b/ipconfig.cc
index 092e279..b386c46 100644
--- a/ipconfig.cc
+++ b/ipconfig.cc
@@ -12,7 +12,7 @@
 
 namespace shill {
 
-IPConfig::IPConfig(const Device &device) : device_(device) {
+IPConfig::IPConfig(DeviceConstRefPtr device) : device_(device) {
   VLOG(2) << "IPConfig created.";
 }
 
@@ -21,7 +21,7 @@
 }
 
 const string &IPConfig::GetDeviceName() const {
-  return device().UniqueName();
+  return device()->UniqueName();
 }
 
 bool IPConfig::Request() {