Introduce DEFINE_DOCUMENT_TYPE_CASTS, and use it

Source/core/html/HTMLDocument.h

Index: Source/core/html/HTMLDocument.h
diff --git a/Source/core/html/HTMLDocument.h b/Source/core/html/HTMLDocument.h
index 661c004d3ac3c4e0765d4e79a16316c03a6c0b77..aa52f77ac85cd643818d42e01a3e48b61890b195 100644
--- a/Source/core/html/HTMLDocument.h
+++ b/Source/core/html/HTMLDocument.h
@@ -109,32 +109,7 @@ inline bool HTMLDocument::hasExtraNamedItem(const AtomicString& name)
     return m_extraNamedItemCounts.contains(name);
 }
 
-inline HTMLDocument* toHTMLDocument(Document* document)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!document || document->isHTMLDocument());
-    return static_cast<HTMLDocument*>(document);
-}
-
-inline const HTMLDocument* toHTMLDocument(const Document* document)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!document || document->isHTMLDocument());
-    return static_cast<const HTMLDocument*>(document);
-}
-
-inline HTMLDocument& toHTMLDocument(Document& document)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(document.isHTMLDocument());
-    return static_cast<HTMLDocument&>(document);
-}
-
-inline const HTMLDocument& toHTMLDocument(const Document& document)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(document.isHTMLDocument());
-    return static_cast<const HTMLDocument&>(document);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toHTMLDocument(const HTMLDocument*);
+DEFINE_DOCUMENT_TYPE_CASTS(HTMLDocument);
 
 } // namespace WebCore