diff --git a/system_state.h b/system_state.h
index 65d4e48..e32aa0e 100644
--- a/system_state.h
+++ b/system_state.h
@@ -5,6 +5,8 @@
 #ifndef UPDATE_ENGINE_SYSTEM_STATE_H_
 #define UPDATE_ENGINE_SYSTEM_STATE_H_
 
+#include "update_engine/dbus_proxies.h"
+
 class MetricsLibraryInterface;
 
 namespace chromeos_update_manager {
@@ -26,7 +28,6 @@
 // the required classes.
 class ClockInterface;
 class ConnectionManagerInterface;
-class GpioHandler;
 class HardwareInterface;
 class OmahaRequestParams;
 class P2PManager;
@@ -87,6 +88,9 @@
   // Returns a pointer to the UpdateManager singleton.
   virtual chromeos_update_manager::UpdateManager* update_manager() = 0;
 
+  // DBus proxies. Mocked during test.
+  virtual org::chromium::PowerManagerProxyInterface* power_manager_proxy() = 0;
+
   // If true, this is the first instance of the update engine since the system
   // restarted. Important for tracking whether you are running instance of the
   // update engine on first boot or due to a crash/restart.