modules/javafx.web/src/main/native/Source/WebCore/rendering/RenderBox.h

@@ -59,14 +59,10 @@
     bool backgroundIsKnownToBeOpaqueInRect(const LayoutRect& localRect) const final;
 
     // Returns false for the body renderer if its background is propagated to the root.
     bool paintsOwnBackground() const;
 
-    // Use this with caution! No type checking is done!
-    RenderBox* firstChildBox() const;
-    RenderBox* lastChildBox() const;
-
     LayoutUnit x() const { return m_frameRect.x(); }
     LayoutUnit y() const { return m_frameRect.y(); }
     LayoutUnit width() const { return m_frameRect.width(); }
     LayoutUnit height() const { return m_frameRect.height(); }
 

@@ -176,14 +172,16 @@
     void addFocusRingRects(Vector<LayoutRect>&, const LayoutPoint& additionalOffset, const RenderLayerModelObject* paintContainer = nullptr) override;
 
     FloatRect repaintRectInLocalCoordinates() const override { return borderBoxRect(); }
     FloatRect objectBoundingBox() const override { return borderBoxRect(); }
 
-    // Use this with caution! No type checking is done!
+    // Note these functions are not equivalent of childrenOfType<RenderBox>
+    RenderBox* parentBox() const;
+    RenderBox* firstChildBox() const;
+    RenderBox* lastChildBox() const;
     RenderBox* previousSiblingBox() const;
     RenderBox* nextSiblingBox() const;
-    RenderBox* parentBox() const;
 
     // Visual and layout overflow are in the coordinate space of the box.  This means that they aren't purely physical directions.
     // For horizontal-tb and vertical-lr they will match physical directions, but for horizontal-bt and vertical-rl, the top/bottom and left/right
     // respectively are flipped when compared to their physical counterparts.  For example minX is on the left in vertical-lr,
     // but it is on the right in vertical-rl.

@@ -738,33 +736,53 @@
 private:
     // Used to store state between styleWillChange and styleDidChange
     static bool s_hadOverflowClip;
 };
 
-inline RenderBox* RenderBox::previousSiblingBox() const
-{
-    return downcast<RenderBox>(previousSibling());
-}
-
-inline RenderBox* RenderBox::nextSiblingBox() const
-{
-    return downcast<RenderBox>(nextSibling());
-}
-
 inline RenderBox* RenderBox::parentBox() const
 {
+    if (is<RenderBox>(parent()))
     return downcast<RenderBox>(parent());
+
+    ASSERT(!parent());
+    return nullptr;
 }
 
 inline RenderBox* RenderBox::firstChildBox() const
 {
+    if (is<RenderBox>(firstChild()))
     return downcast<RenderBox>(firstChild());
+
+    ASSERT(!firstChild());
+    return nullptr;
 }
 
 inline RenderBox* RenderBox::lastChildBox() const
 {
+    if (is<RenderBox>(lastChild()))
     return downcast<RenderBox>(lastChild());
+
+    ASSERT(!lastChild());
+    return nullptr;
+}
+
+inline RenderBox* RenderBox::previousSiblingBox() const
+{
+    if (is<RenderBox>(previousSibling()))
+        return downcast<RenderBox>(previousSibling());
+
+    ASSERT(!previousSibling());
+    return nullptr;
+}
+
+inline RenderBox* RenderBox::nextSiblingBox() const
+{
+    if (is<RenderBox>(nextSibling()))
+        return downcast<RenderBox>(nextSibling());
+
+    ASSERT(!nextSibling());
+    return nullptr;
 }
 
 inline void RenderBox::setInlineBoxWrapper(InlineElementBox* boxWrapper)
 {
     if (boxWrapper) {