--- a/widget/gtk/nsNativeThemeGTK.cpp
+++ b/widget/gtk/nsNativeThemeGTK.cpp
@@ -47,16 +47,17 @@
 #  endif
 #endif
 
 #include <algorithm>
 #include <dlfcn.h>
 
 using namespace mozilla;
 using namespace mozilla::gfx;
+using namespace mozilla::widget;
 
 NS_IMPL_ISUPPORTS_INHERITED(nsNativeThemeGTK, nsNativeTheme, nsITheme,
                                                              nsIObserver)
 
 static int gLastGdkError;
 
 nsNativeThemeGTK::nsNativeThemeGTK()
 {