Introduce isHTMLAnchorElement and toHTMLAnchorElement

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 0358d20e1f34b833c95a6477d63acf0bc488008a..26bb4744a55fa1634f9689e53871cc1afbff85be 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -2454,8 +2454,8 @@ void Document::updateBaseURL()
         // Base URL change changes any relative visited links.
         // FIXME: There are other URLs in the tree that would need to be re-evaluated on dynamic base URL change. Style should be invalidated too.
         for (Element* element = ElementTraversal::firstWithin(this); element; element = ElementTraversal::next(element)) {
-            if (element->hasTagName(aTag))
-                static_cast<HTMLAnchorElement*>(element)->invalidateCachedVisitedLinkHash();
+            if (isHTMLAnchorElement(element))
+                toHTMLAnchorElement(element)->invalidateCachedVisitedLinkHash();
         }
     }
 }