[shill] add flimflam DebugTags methods

They are ignored for now in shill, but should probably be implemented soon. The
debug daemon needs them to ask flimflam to start debugging.

BUG=chromium-os:26091
TEST=build

Change-Id: Ia16c411e5b4f6d34212b154a40fab2b8d3f88f62
Signed-off-by: Elly Jones <ellyjones@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/15590
diff --git a/manager_dbus_adaptor.cc b/manager_dbus_adaptor.cc
index 1745b11..b1996e1 100644
--- a/manager_dbus_adaptor.cc
+++ b/manager_dbus_adaptor.cc
@@ -220,4 +220,16 @@
   e.ToDBusError(&error);
 }
 
+std::string ManagerDBusAdaptor::GetDebugTags(::DBus::Error &/*error*/) {
+  return "";
+}
+
+void ManagerDBusAdaptor::SetDebugTags(const std::string &/*tags*/,
+                                      ::DBus::Error &/*error*/) {
+}
+
+std::string ManagerDBusAdaptor::ListDebugTags(::DBus::Error &/*error*/) {
+  return "";
+}
+
 }  // namespace shill