diff --git a/system_state.h b/system_state.h
index a04c434..772205c 100644
--- a/system_state.h
+++ b/system_state.h
@@ -10,6 +10,7 @@
 #include <policy/libpolicy.h>
 
 #include <update_engine/connection_manager.h>
+#include <update_engine/gpio_handler.h>
 #include <update_engine/payload_state.h>
 #include <update_engine/prefs.h>
 
@@ -46,6 +47,9 @@
 
   // Gets the interface for the payload state object.
   virtual PayloadStateInterface* payload_state() = 0;
+
+  // Returns a pointer to the GPIO handler.
+  virtual GpioHandler* gpio_handler() const = 0;
 };
 
 // A real implementation of the SystemStateInterface which is
@@ -83,9 +87,14 @@
     return &payload_state_;
   }
 
+  // Returns a pointer to the GPIO handler.
+  virtual inline GpioHandler* gpio_handler() const {
+    return gpio_handler_.get();
+  }
+
   // Initializs this concrete object. Other methods should be invoked only
   // if the object has been initialized successfully.
-  bool Initialize();
+  bool Initialize(bool enable_gpio);
 
 private:
   // The latest device policy object from the policy provider.
@@ -104,6 +113,13 @@
   // All state pertaining to payload state such as
   // response, URL, backoff states.
   PayloadState payload_state_;
+
+  // Pointer to a GPIO handler and other needed modules (note that the order of
+  // declaration significant for destruction, as the latter depends on the
+  // former).
+  scoped_ptr<UdevInterface> udev_iface_;
+  scoped_ptr<FileDescriptor> file_descriptor_;
+  scoped_ptr<GpioHandler> gpio_handler_;
 };
 
 }  // namespace chromeos_update_engine