Introduce DEFINE_DOCUMENT_TYPE_CASTS, and use it

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index 2c064035ac5c807604ac82cc352518b34eb0ac6d..861c304b69e311fae0ec8d23cabc8619fe25e64f 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -1347,6 +1347,9 @@ inline const Document* toDocument(const ExecutionContext* executionContext)
 
 DEFINE_NODE_TYPE_CASTS(Document, isDocumentNode());
 
+#define DEFINE_DOCUMENT_TYPE_CASTS(thisType) \
+    DEFINE_TYPE_CASTS(thisType, Document, document, document->is##thisType(), document.is##thisType())
+
 // All these varations are needed to avoid ambiguous overloads with the Node and TreeScope versions.
 inline bool operator==(const Document& a, const Document& b) { return &a == &b; }
 inline bool operator==(const Document& a, const Document* b) { return &a == b; }