Change namespace from ui to gfx for NativePixmap related code

ui/ozone/platform/drm/client_native_pixmap_factory_gbm.h

Index: ui/ozone/platform/drm/client_native_pixmap_factory_gbm.h
diff --git a/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.h b/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.h
index 1932c9158b813e873c6f1dc4437d47879688f6bc..05506d6db43e583aed2738343ea3b32b824d8e36 100644
--- a/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.h
+++ b/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.h
@@ -5,12 +5,14 @@
 #ifndef UI_OZONE_PLATFORM_DRM_CLIENT_NATIVE_PIXMAP_FACTORY_GBM_H_
 #define UI_OZONE_PLATFORM_DRM_CLIENT_NATIVE_PIXMAP_FACTORY_GBM_H_
 
-namespace ui {
-
+namespace gfx {
 class ClientNativePixmapFactory;
+}
+
+namespace ui {
 
 // Constructor hook for use in constructor_list.cc
-ClientNativePixmapFactory* CreateClientNativePixmapFactoryGbm();
+gfx::ClientNativePixmapFactory* CreateClientNativePixmapFactoryGbm();
 
 }  // namespace ui