Change namespace from ui to gfx for NativePixmap related code

ui/ozone/platform/headless/client_native_pixmap_factory_headless.h

Index: ui/ozone/platform/headless/client_native_pixmap_factory_headless.h
diff --git a/ui/ozone/platform/headless/client_native_pixmap_factory_headless.h b/ui/ozone/platform/headless/client_native_pixmap_factory_headless.h
index 675eec15929c0cba2014105490897a2bed42080b..1eac601a98edb96a78010e6cda5c0abc08bdc777 100644
--- a/ui/ozone/platform/headless/client_native_pixmap_factory_headless.h
+++ b/ui/ozone/platform/headless/client_native_pixmap_factory_headless.h
@@ -5,12 +5,14 @@
 #ifndef UI_OZONE_PLATFORM_HEADLESS_CLIENT_NATIVE_PIXMAP_FACTORY_HEADLESS_H_
 #define UI_OZONE_PLATFORM_HEADLESS_CLIENT_NATIVE_PIXMAP_FACTORY_HEADLESS_H_
 
-namespace ui {
-
+namespace gfx {
 class ClientNativePixmapFactory;
+}
+
+namespace ui {
 
 // Constructor hook for use in constructor_list.cc
-ClientNativePixmapFactory* CreateClientNativePixmapFactoryHeadless();
+gfx::ClientNativePixmapFactory* CreateClientNativePixmapFactoryHeadless();
 
 }  // namespace ui