Fieldset NG: Fix mask painting

PaintMask() should take care of the rendered legend.

- NGBoxFragmentPainter::PaintMask() checks if the fragment is a fieldset
  container, and delegate to NGFieldsetPainter if so.
- NGFieldsetPainter::PaintMask() creates FieldsetPaintInfo, and adjust
  the paint rectangle.

- NGFieldsetPainter now has CreateFieldsetPaintInfo() to share
  FieldsetPaintInfo creation logic between PaintMask() and
  PaintBoxDecorationBackground().
- Merge NGFieldsetPainter::PaintFieldsetDecorationBackground() into
  PaintDecorationBackground().

Bug: 875235
Change-Id: If6f7e709db538f99d699458938f5a1b2db9a8e47
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2348229
Commit-Queue: Kent Tamura <tkent@chromium.org>
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796808}

third_party/blink/renderer/core/paint/ng/ng_box_fragment_painter.cc

@@ -905,6 +905,12 @@ void NGBoxFragmentPainter::PaintMask(const PaintInfo& paint_info,
           paint_info.context, GetDisplayItemClient(), paint_info.phase))
     return;
 
+  if (physical_box_fragment.IsFieldsetContainer()) {
+    NGFieldsetPainter(box_fragment_)
+        .PaintMask(paint_info, paint_offset, BorderEdges());
+    return;
+  }
+
   // TODO(eae): Switch to LayoutNG version of BackgroundImageGeometry.
   BackgroundImageGeometry geometry(*static_cast<const LayoutBoxModelObject*>(
       box_fragment_.GetLayoutObject()));

third_party/blink/renderer/core/paint/ng/ng_fieldset_painter.cc

@@ -20,38 +20,15 @@
 
 namespace blink {
 
-void NGFieldsetPainter::PaintBoxDecorationBackground(
-    const PaintInfo& paint_info,
-    const PhysicalOffset& paint_offset) {
+FieldsetPaintInfo NGFieldsetPainter::CreateFieldsetPaintInfo() const {
   const NGLink* legend = nullptr;
   if (!fieldset_.Children().empty()) {
     const auto& first_child = fieldset_.Children().front();
     if (first_child->IsRenderedLegend())
       legend = &first_child;
   }
-
-  // Paint the fieldset (background, other decorations, and) border, with the
-  // cutout hole for the legend.
-  PaintFieldsetDecorationBackground(legend, paint_info, paint_offset);
-}
-
-void NGFieldsetPainter::PaintFieldsetDecorationBackground(
-    const NGLink* legend,
-    const PaintInfo& paint_info,
-    const PhysicalOffset& paint_offset) {
-  PhysicalSize fieldset_size(fieldset_.Size());
-  PhysicalRect paint_rect(paint_offset, fieldset_size);
+  const PhysicalSize fieldset_size(fieldset_.Size());
   const auto& fragment = fieldset_;
-  BoxDecorationData box_decoration_data(paint_info, fragment);
-  // TODO(crbug.com/786475): Fieldset should not scroll.
-  DCHECK(!box_decoration_data.IsPaintingScrollingBackground());
-  if (!box_decoration_data.ShouldPaint())
-    return;
-
-  if (DrawingRecorder::UseCachedDrawingIfPossible(
-          paint_info.context, *fieldset_.GetLayoutObject(), paint_info.phase))
-    return;
-
   LayoutRectOutsets fieldset_borders = fragment.Borders().ToLayoutRectOutsets();
   const ComputedStyle& style = fieldset_.Style();
   PhysicalRect legend_border_box;
@@ -85,8 +62,29 @@ void NGFieldsetPainter::PaintFieldsetDecorationBackground(
     legend_border_box.offset = legend_logical_offset.ConvertToPhysical(
         writing_direction, fieldset_size, legend_border_box.size);
   }
-  FieldsetPaintInfo fieldset_paint_info(style, fieldset_size, fieldset_borders,
-                                        legend_border_box);
+  return FieldsetPaintInfo(style, fieldset_size, fieldset_borders,
+                           legend_border_box);
+}
+
+// Paint the fieldset (background, other decorations, and) border, with the
+// cutout hole for the legend.
+void NGFieldsetPainter::PaintBoxDecorationBackground(
+    const PaintInfo& paint_info,
+    const PhysicalOffset& paint_offset) {
+  PhysicalSize fieldset_size(fieldset_.Size());
+  PhysicalRect paint_rect(paint_offset, fieldset_size);
+  BoxDecorationData box_decoration_data(paint_info, fieldset_);
+  // TODO(crbug.com/786475): Fieldset should not scroll.
+  DCHECK(!box_decoration_data.IsPaintingScrollingBackground());
+  if (!box_decoration_data.ShouldPaint())
+    return;
+
+  if (DrawingRecorder::UseCachedDrawingIfPossible(
+          paint_info.context, *fieldset_.GetLayoutObject(), paint_info.phase))
+    return;
+
+  const ComputedStyle& style = fieldset_.Style();
+  FieldsetPaintInfo fieldset_paint_info = CreateFieldsetPaintInfo();
   PhysicalRect contracted_rect(paint_rect);
   contracted_rect.Contract(fieldset_paint_info.border_outsets);
 
@@ -128,4 +126,22 @@ void NGFieldsetPainter::PaintFieldsetDecorationBackground(
   }
 }
 
+void NGFieldsetPainter::PaintMask(const PaintInfo& paint_info,
+                                  const PhysicalOffset& paint_offset,
+                                  const NGBorderEdges& border_edges) {
+  // TODO(eae): Switch to LayoutNG version of BackgroundImageGeometry.
+  const LayoutObject& layout_object = *fieldset_.GetLayoutObject();
+  BackgroundImageGeometry geometry(
+      static_cast<const LayoutBoxModelObject&>(layout_object));
+
+  NGBoxFragmentPainter ng_box_painter(fieldset_);
+  DrawingRecorder recorder(paint_info.context, layout_object, paint_info.phase,
+                           ng_box_painter.VisualRect(paint_offset));
+  PhysicalRect paint_rect(paint_offset, fieldset_.Size());
+  paint_rect.Contract(CreateFieldsetPaintInfo().border_outsets);
+  ng_box_painter.PaintMaskImages(paint_info, paint_rect, layout_object,
+                                 geometry, border_edges.line_left,
+                                 border_edges.line_right);
+}
+
 }  // namespace blink

third_party/blink/renderer/core/paint/ng/ng_fieldset_painter.h

@@ -10,7 +10,8 @@
 namespace blink {
 
 class NGPhysicalBoxFragment;
-struct NGLink;
+struct FieldsetPaintInfo;
+struct NGBorderEdges;
 struct PaintInfo;
 struct PhysicalOffset;
 
@@ -22,11 +23,10 @@ class NGFieldsetPainter {
       : fieldset_(fieldset) {}
 
   void PaintBoxDecorationBackground(const PaintInfo&, const PhysicalOffset&);
+  void PaintMask(const PaintInfo&, const PhysicalOffset&, const NGBorderEdges&);
 
  private:
-  void PaintFieldsetDecorationBackground(const NGLink* legend,
-                                         const PaintInfo&,
-                                         const PhysicalOffset&);
+  FieldsetPaintInfo CreateFieldsetPaintInfo() const;
 
   const NGPhysicalBoxFragment& fieldset_;
 };

third_party/blink/web_tests/TestExpectations

@@ -1283,8 +1283,6 @@ virtual/layout_ng_fragment_traversal/external/wpt/css/CSS2/text/* [ Skip ]
 
 # Size containment
 crbug.com/875235 external/wpt/css/css-sizing/contain-intrinsic-size/contain-intrinsic-size-014.html [ Failure ]
-# Mask paiting area
-crbug.com/875235 paint/masks/fieldset-mask.html [ Failure ]
 
 
 # ====== LayoutNG-only failures until here ======