[LFC] Add ElementBox::hasOutOfFlowChild

https://bugs.webkit.org/show_bug.cgi?id=260805

Reviewed by Antti Koivisto.

This is in preparation for out-of-flow box static position (we need to know if the IFC should need to run inflow layout).

* Source/WebCore/layout/layouttree/LayoutElementBox.cpp:
(WebCore::Layout::ElementBox::hasOutOfFlowChild const):
* Source/WebCore/layout/layouttree/LayoutElementBox.h:

Canonical link: https://commits.webkit.org/267397@main

Source/WebCore/layout/formattingContexts/inline/InlineFormattingContext.cpp

@@ -71,7 +71,7 @@ InlineLayoutResult InlineFormattingContext::layoutInFlowAndFloatContent(const Co
 {
     auto& floatingState = inlineLayoutState.parentBlockLayoutState().floatingState();
     if (!root().hasInFlowChild()) {
-        // Float and/or out-of-flow only content does not support partial layout.
+        // Float only content does not support partial layout.
         ASSERT(!lineDamage);
         layoutFloatContentOnly(constraints, floatingState);
         return { { }, InlineLayoutResult::Range::Full };
@@ -239,13 +239,6 @@ void InlineFormattingContext::layoutFloatContentOnly(const ConstraintsForInlineC
             floatingState.append(floatingContext.toFloatItem(floatBox, floatBoxGeometry));
             continue;
         }
-        if (inlineItem.isOpaque()) {
-            auto& opaqueBox = inlineItem.layoutBox();
-            if (opaqueBox.isOutOfFlowPositioned()) {
-                // FIXME: set the static position.
-                continue;
-            }
-        }
         ASSERT_NOT_REACHED();
     }
 }

Source/WebCore/layout/layouttree/LayoutElementBox.cpp

@@ -101,6 +101,15 @@ const Box* ElementBox::lastInFlowOrFloatingChild() const
     return nullptr;
 }
 
+bool ElementBox::hasOutOfFlowChild() const
+{
+    for (auto* child = this->firstChild(); child; child = child->nextSibling()) {
+        if (child->isOutOfFlowPositioned())
+            return true;
+    }
+    return false;
+}
+
 void ElementBox::appendChild(UniqueRef<Box> childRef)
 {
     insertChild(WTFMove(childRef), m_lastChild.get());

Source/WebCore/layout/layouttree/LayoutElementBox.h

@@ -66,6 +66,7 @@ class ElementBox : public Box {
     bool hasChild() const { return firstChild(); }
     bool hasInFlowChild() const { return firstInFlowChild(); }
     bool hasInFlowOrFloatingChild() const { return firstInFlowOrFloatingChild(); }
+    bool hasOutOfFlowChild() const;
 
     void appendChild(UniqueRef<Box>);
     void insertChild(UniqueRef<Box>, Box* beforeChild = nullptr);