Introduce isHTMLAnchorElement and toHTMLAnchorElement

Source/core/dom/TreeScope.cpp

Index: Source/core/dom/TreeScope.cpp
diff --git a/Source/core/dom/TreeScope.cpp b/Source/core/dom/TreeScope.cpp
index 1564015de4f9670fb88d6fe69c8555e25b1c540e..9cd02cbcf3d4ec0c4b439280162f94870e3f7e10 100644
--- a/Source/core/dom/TreeScope.cpp
+++ b/Source/core/dom/TreeScope.cpp
@@ -302,8 +302,8 @@ Element* TreeScope::findAnchor(const String& name)
     if (Element* element = getElementById(name))
         return element;
     for (Element* element = ElementTraversal::firstWithin(rootNode()); element; element = ElementTraversal::next(element)) {
-        if (element->hasTagName(aTag)) {
-            HTMLAnchorElement* anchor = static_cast<HTMLAnchorElement*>(element);
+        if (isHTMLAnchorElement(element)) {
+            HTMLAnchorElement* anchor = toHTMLAnchorElement(element);
             if (rootNode()->document()->inQuirksMode()) {
                 // Quirks mode, case insensitive comparison of names.
                 if (equalIgnoringCase(anchor->name(), name))