Cast highestEnclosingNodeOfType() return value to tighter type

Source/core/html/HTMLQuoteElement.h

Index: Source/core/html/HTMLQuoteElement.h
diff --git a/Source/core/html/HTMLQuoteElement.h b/Source/core/html/HTMLQuoteElement.h
index 185f243f8f736ce9c415d6723a6157c6d4932088..d5a646c27c8e79ae1d914546fe2b6fc8eefddb62 100644
--- a/Source/core/html/HTMLQuoteElement.h
+++ b/Source/core/html/HTMLQuoteElement.h
@@ -41,6 +41,13 @@ private:
     virtual const QualifiedName& subResourceAttributeName() const OVERRIDE;
 };
 
+inline bool isHTMLQuoteElement(const HTMLElement& element)
+{
+    return element.hasTagName(HTMLNames::qTag) || element.hasTagName(HTMLNames::blockquoteTag);
+}
+
+DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLQuoteElement);
+
 } //namespace
 
 #endif