[shill] Add getting/setting for ipconfig properties

BUG=chromium-os:17261
TEST=unit tests

Change-Id: I96aed7c979c7913c568d00ce408a662898969d76
Reviewed-on: http://gerrit.chromium.org/gerrit/3583
Tested-by: Chris Masone <cmasone@chromium.org>
Reviewed-by: Darin Petkov <petkov@chromium.org>
diff --git a/property_store.h b/property_store.h
index 42f3cd4..485f429 100644
--- a/property_store.h
+++ b/property_store.h
@@ -89,10 +89,9 @@
   void RegisterConstInt32(const std::string &name, const int32 *prop);
   void RegisterString(const std::string &name, std::string *prop);
   void RegisterConstString(const std::string &name, const std::string *prop);
-  void RegisterStringmap(const std::string &name,
-                         std::map<std::string, std::string> *prop);
-  void RegisterConstStringmap(const std::string &name,
-                              const std::map<std::string, std::string> *prop);
+  void RegisterStringmap(const std::string &name, Stringmap *prop);
+  void RegisterConstStringmap(const std::string &name, const Stringmap *prop);
+  void RegisterStrings(const std::string &name, Strings *prop);
   void RegisterConstUint8(const std::string &name, const uint8 *prop);
   void RegisterUint16(const std::string &name, uint16 *prop);
   void RegisterConstUint16(const std::string &name, const uint16 *prop);