Extract draw merge temporary paint branch

src/legacy_canvas_draw_merge_services.h

@@ -124,6 +124,28 @@ template <
     };
 }
 
+template <
+    typename Setup,
+    typename BindSamplers,
+    typename BindTextures,
+    typename Draw,
+    typename UnbindTextures>
+[[nodiscard]] inline LegacyCanvasDrawMergeTemporaryCompositeExecution make_legacy_canvas_draw_merge_temporary_paint_composite(
+    Setup&& setup,
+    BindSamplers&& bind_samplers,
+    BindTextures&& bind_textures,
+    Draw&& draw,
+    UnbindTextures&& unbind_textures)
+{
+    return LegacyCanvasDrawMergeTemporaryCompositeExecution {
+        .setup = std::forward<Setup>(setup),
+        .bind_samplers = std::forward<BindSamplers>(bind_samplers),
+        .bind_textures = std::forward<BindTextures>(bind_textures),
+        .draw = std::forward<Draw>(draw),
+        .unbind_textures = std::forward<UnbindTextures>(unbind_textures),
+    };
+}
+
 struct LegacyCanvasDrawMergePlaneSetupUniforms {
     LegacyCanvasDrawMergeCheckerboardUniforms checkerboard;
     bool use_blend = false;