Refactor RenderTreeBuilder and expose special <dialog>

Source/core/html/HTMLDialogElement.cpp

Index: Source/core/html/HTMLDialogElement.cpp
diff --git a/Source/core/html/HTMLDialogElement.cpp b/Source/core/html/HTMLDialogElement.cpp
index 59d5bc04a5e2789c70139cbf99358d29267ecef9..42a503d30dcea95d4081a5174ac472d31f69eeed 100644
--- a/Source/core/html/HTMLDialogElement.cpp
+++ b/Source/core/html/HTMLDialogElement.cpp
@@ -201,11 +201,4 @@ void HTMLDialogElement::defaultEventHandler(Event* event)
     HTMLElement::defaultEventHandler(event);
 }
 
-bool HTMLDialogElement::shouldBeReparentedUnderRenderView(const RenderStyle* style) const
-{
-    if (style && style->position() == AbsolutePosition)
-        return true;
-    return Element::shouldBeReparentedUnderRenderView(style);
-}
-
 } // namespace WebCore