diff --git a/prefs_interface.h b/prefs_interface.h
index 6c0a741..cdc6efe 100644
--- a/prefs_interface.h
+++ b/prefs_interface.h
@@ -18,6 +18,8 @@
 
 class PrefsInterface {
  public:
+  virtual ~PrefsInterface() {}
+
   // Gets a string |value| associated with |key|. Returns true on
   // success, false on failure (including when the |key| is not
   // present in the store).
@@ -52,8 +54,6 @@
   // Returns true if successfully deleted the file corresponding to
   // this key. Calling with non-existent keys does nothing.
   virtual bool Delete(const std::string& key) = 0;
-
-  virtual ~PrefsInterface() {}
 };
 
 }  // namespace chromeos_update_engine