diff --git a/src/device_manager.cc b/src/device_manager.cc
index e99ca4d..cb575b8 100644
--- a/src/device_manager.cc
+++ b/src/device_manager.cc
@@ -105,6 +105,10 @@
   return component_manager_->GetTraits();
 }
 
+void DeviceManager::AddTraitDefsChangedCallback(const base::Closure& callback) {
+  component_manager_->AddTraitDefChangedCallback(callback);
+}
+
 bool DeviceManager::AddComponent(const std::string& name,
                                  const std::vector<std::string>& traits,
                                  ErrorPtr* error) {