Interaction Regions generation should get geometry from the RenderTree

https://bugs.webkit.org/show_bug.cgi?id=272328
<rdar://125901606>

Reviewed by Alan Baradlay.

Interaction Regions generation happens during the EventRegion paint
phase, and should get geometry from the RenderTree instead of going
through the DOM.
Replace the calls to `Element#boundingClientRect()` with a custom
function based on `RenderObject#absoluteQuads()`.

* Source/WebCore/page/InteractionRegion.cpp:
(WebCore::absoluteBoundingRect):
(WebCore::interactionRegionForRenderedRegion):

Canonical link: https://commits.webkit.org/277290@main

Source/WebCore/page/InteractionRegion.cpp

@@ -225,6 +225,13 @@ static bool isGuardContainer(const Element& element)
     return hasTransparentContainerStyle(renderer.style());
 }
 
+static FloatRect absoluteBoundingRect(const RenderObject& renderer)
+{
+    Vector<FloatQuad> quads;
+    renderer.absoluteQuads(quads);
+    return unitedBoundingBoxes(quads);
+}
+
 static bool cachedImageIsPhoto(const CachedImage& cachedImage)
 {
     if (cachedImage.errorOccurred())
@@ -423,16 +430,16 @@ std::optional<InteractionRegion> interactionRegionForRenderedRegion(RenderObject
     std::optional<Path> clipPath = std::nullopt;
     RefPtr styleClipPath = regionRenderer.style().clipPath();
 
-    if (styleClipPath && styleClipPath->type() == PathOperation::OperationType::Shape) {
-        auto boundingRect = originalElement->boundingClientRect();
+    if (styleClipPath && styleClipPath->type() == PathOperation::OperationType::Shape && originalElement) {
+        auto boundingRect = absoluteBoundingRect(regionRenderer);
         clipPath = styleClipPath->getPath(TransformOperationData(FloatRect(FloatPoint(), boundingRect.size())));
     } else if (iconImage && originalElement) {
         LayoutRect imageRect(rect);
         Ref shape = Shape::createRasterShape(iconImage.get(), 0, imageRect, imageRect, WritingMode::HorizontalTb, 0);
         Shape::DisplayPaths paths;
         shape->buildDisplayPaths(paths);
         auto path = paths.shape;
-        auto boundingRect = originalElement->boundingClientRect();
+        auto boundingRect = absoluteBoundingRect(regionRenderer);
         path.translate(FloatSize(-boundingRect.x(), -boundingRect.y()));
         clipPath = path;
     } else if (svgClipElements) {