[masonry] Expose grid items positions and sizes to Web Inspector

https://bugs.webkit.org/show_bug.cgi?id=267736
rdar://problem/121219933

Reviewed by Sammy Gill.

Masonry differs from Grid in only having one axis. This does not allow simple drawing
straight lines. The Web Inspector can instead draw boxes around each item, which this patch
is exposing in a simpler format.

This patch is not exclusive to masonry and can be used for all returning all grid items
layout rects.

* Source/WebCore/rendering/RenderGrid.cpp:
(WebCore::RenderGrid::gridItemsLayoutRects):
* Source/WebCore/rendering/RenderGrid.h:

Canonical link: https://commits.webkit.org/273232@main

Source/WebCore/rendering/RenderGrid.cpp

@@ -1022,6 +1022,16 @@ LayoutUnit RenderGrid::masonryContentSize() const
     return m_masonryLayout.gridContentSize();
 }
 
+Vector<LayoutRect> RenderGrid::gridItemsLayoutRects()
+{
+    Vector<LayoutRect> items;
+
+    for (RenderBox* child = currentGrid().orderIterator().first(); child; child = currentGrid().orderIterator().next())
+        items.append(child->frameRect());
+
+    return items;
+}
+
 void RenderGrid::performGridItemsPreLayout(const GridTrackSizingAlgorithm& algorithm, const ShouldUpdateGridAreaLogicalSize shouldUpdateGridAreaLogicalSize) const
 {
     ASSERT(!algorithm.grid().needsItemsPlacement());

Source/WebCore/rendering/RenderGrid.h

@@ -128,6 +128,7 @@ class RenderGrid final : public RenderBlock {
     LayoutUnit gridGap(GridTrackSizingDirection, std::optional<LayoutUnit> availableSize) const;
 
     LayoutUnit masonryContentSize() const;
+    Vector<LayoutRect> gridItemsLayoutRects();
 private:
     friend class GridTrackSizingAlgorithm;
     friend class GridMasonryLayout;