[shill] device, service objects need to register unique paths

BUG=chromium-os:15752
TEST=unit tests

Change-Id: I54a5b1fb3e156fb62ffff0bc49a411135c01a1d0
Reviewed-on: http://gerrit.chromium.org/gerrit/1897
Reviewed-by: Chris Masone <cmasone@chromium.org>
Tested-by: Chris Masone <cmasone@chromium.org>
diff --git a/device.h b/device.h
index 403400a..1be39ad 100644
--- a/device.h
+++ b/device.h
@@ -43,7 +43,6 @@
          const std::string& link_name,
          int interface_index);
   virtual ~Device();
-  const std::string& Name() const;
 
   virtual void Start();
   virtual void Stop();
@@ -52,6 +51,10 @@
   virtual void LinkEvent(unsigned flags, unsigned change);
   virtual void Scan();
 
+  // Returns a string that is guaranteed to uniquely identify this
+  // Device instance.
+  const std::string& UniqueName() const;
+
  protected:
   std::vector<scoped_refptr<Service> > services_;
   std::string link_name_;