Share retained stroke face sample dispatch

docs/modernization/roadmap.md

@@ -3133,6 +3133,10 @@ Results:
   retained sampler/texture-slot binding, and final plane draw ordering, while
   mixer framebuffer/state setup and per-plane shader material/MVP preparation
   remain in the legacy Canvas path.
+- `Canvas::stroke_draw_samples()` now shares
+  `execute_legacy_canvas_stroke_face_sample_polygon(...)` for face-indexed
+  destination bind/copy/unbind and brush upload/draw dispatch, while concrete
+  GL object callbacks remain in the legacy Canvas path.
 - `NodeStrokePreview::stroke_draw_mix()` now shares one local helper for mixer
   framebuffer bind/unbind, viewport/scissor/blend state, texture-slot
   binding, and final plane draw, while material planning and shader uniform