FrameSet NG: Add three methods to LayoutNGFrameSet

This CL adds:
 * IsChildAllowed()
 * UpdateBlockLayout()
 * GetCursor()

Implementations of IsChildAllowed() and GetCursor() are very similar to
ones of LayoutFrameSet. UpdateBlockLayout() implementation is same as
ones of LayoutNGGrid and LayoutNGFlexibleBox.

This CL has no behaivor changes due to a disabled runtime flag.

Bug: 1346221
Change-Id: Iad457b7c41ee78b559a17886a5df2efc4063781a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3828775
Commit-Queue: Koji Ishii <kojii@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Auto-Submit: Kent Tamura <tkent@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1034969}

third_party/blink/renderer/core/layout/ng/layout_ng_frame_set.cc

@@ -5,6 +5,8 @@
 #include "third_party/blink/renderer/core/layout/ng/layout_ng_frame_set.h"
 
 #include "third_party/blink/renderer/core/html/html_frame_set_element.h"
+#include "third_party/blink/renderer/platform/cursors.h"
+#include "ui/base/cursor/cursor.h"
 
 namespace blink {
 
@@ -22,4 +24,33 @@ bool LayoutNGFrameSet::IsOfType(LayoutObjectType type) const {
   return type == kLayoutObjectNGFrameSet || LayoutNGBlock::IsOfType(type);
 }
 
+bool LayoutNGFrameSet::IsChildAllowed(LayoutObject* child,
+                                      const ComputedStyle&) const {
+  NOT_DESTROYED();
+  return child->IsFrame() || child->IsLayoutNGFrameSet();
+}
+
+void LayoutNGFrameSet::UpdateBlockLayout(bool relayout_children) {
+  if (IsOutOfFlowPositioned())
+    UpdateOutOfFlowBlockLayout();
+  else
+    UpdateInFlowBlockLayout();
+}
+
+CursorDirective LayoutNGFrameSet::GetCursor(const PhysicalOffset& point,
+                                            ui::Cursor& cursor) const {
+  NOT_DESTROYED();
+  const auto& frame_set = *To<HTMLFrameSetElement>(GetNode());
+  gfx::Point rounded_point = ToRoundedPoint(point);
+  if (frame_set.CanResizeRow(rounded_point)) {
+    cursor = RowResizeCursor();
+    return kSetCursor;
+  }
+  if (frame_set.CanResizeColumn(rounded_point)) {
+    cursor = ColumnResizeCursor();
+    return kSetCursor;
+  }
+  return LayoutBox::GetCursor(point, cursor);
+}
+
 }  // namespace blink

third_party/blink/renderer/core/layout/ng/layout_ng_frame_set.h

@@ -16,6 +16,10 @@ class LayoutNGFrameSet final : public LayoutNGBlock {
  private:
   const char* GetName() const override;
   bool IsOfType(LayoutObjectType type) const override;
+  bool IsChildAllowed(LayoutObject* child, const ComputedStyle&) const override;
+  void UpdateBlockLayout(bool relayout_children) override;
+  CursorDirective GetCursor(const PhysicalOffset& point,
+                            ui::Cursor& cursor) const override;
 };
 
 template <>