shill: Add a command line option that controls the default technology order

This can be used to configure a preference for a particular network on a given
device.  For example, a device may want to use the mobile network for all
traffic even if an open wifi network is available.

BUG=chromium:453607
TEST=Added the flag via /etc/init/shill.override and confirmed that dbus GetServiceOrder returned the new order

Change-Id: Ifac0baa4feeaae4a780d4d74f2bd195b4e4dd31d
Reviewed-on: https://chromium-review.googlesource.com/248610
Reviewed-by: Paul Stewart <pstew@chromium.org>
Tested-by: Jason Simmons <jsimmons@chromium.org>
Commit-Queue: Jason Simmons <jsimmons@chromium.org>
diff --git a/manager.h b/manager.h
index f73ee4e..1c99b7e 100644
--- a/manager.h
+++ b/manager.h
@@ -89,7 +89,8 @@
           GLib *glib,
           const std::string &run_directory,
           const std::string &storage_directory,
-          const std::string &user_storage_directory);
+          const std::string &user_storage_directory,
+          const std::vector<Technology::Identifier> &default_technology_order);
   virtual ~Manager();
 
   void AddDeviceToBlackList(const std::string &device_name);