shill: Add Cellular devices to DeviceInfo.

This allows DeviceInfo to handle link messages for Cellular devices, so that we
can bring their interfaces up and down.

BUG=chromium-os:18438,18855
TEST=unit tests, tested on device

Change-Id: I7d642c7302472472c56042f731f746c8b997a149
Reviewed-on: http://gerrit.chromium.org/gerrit/5604
Tested-by: Darin Petkov <petkov@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
diff --git a/manager.h b/manager.h
index b784cdf..154e51c 100644
--- a/manager.h
+++ b/manager.h
@@ -64,9 +64,12 @@
   ServiceRefPtr FindService(const std::string& name);
   std::vector<std::string> EnumerateAvailableServices();
 
+  DeviceInfo *device_info() { return &device_info_; }
   PropertyStore *store() { return &store_; }
 
  private:
+  friend class ManagerAdaptorInterface;
+
   std::string CalculateState();
   std::vector<std::string> AvailableTechnologies();
   std::vector<std::string> ConnectedTechnologies();
@@ -97,8 +100,6 @@
   // Properties to be get/set via PropertyStore calls.
   Properties props_;
   PropertyStore store_;
-
-  friend class ManagerAdaptorInterface;
 };
 
 }  // namespace shill