Introduce HasHTMLTagName functor and use it with ElementTraversal

Source/core/html/HTMLTableRowElement.cpp

Index: Source/core/html/HTMLTableRowElement.cpp
diff --git a/Source/core/html/HTMLTableRowElement.cpp b/Source/core/html/HTMLTableRowElement.cpp
index 8de109ad9a7b4170c30ae73083e38fdb32cfb759..de776cc3a42f27a26382a2b33f9379a75bc9f2e7 100644
--- a/Source/core/html/HTMLTableRowElement.cpp
+++ b/Source/core/html/HTMLTableRowElement.cpp
@@ -81,14 +81,11 @@ int HTMLTableRowElement::rowIndex() const
         }
     }
 
-    for (HTMLElement* child = Traversal<HTMLElement>::firstChild(*table); child; child = Traversal<HTMLElement>::nextSibling(*child)) {
-        if (child->hasTagName(tbodyTag)) {
-            HTMLTableSectionElement* section = toHTMLTableSectionElement(child);
-            for (HTMLTableRowElement* row = Traversal<HTMLTableRowElement>::firstChild(*section); row; row = Traversal<HTMLTableRowElement>::nextSibling(*row)) {
-                if (row == this)
-                    return rIndex;
-                ++rIndex;
-            }
+    for (HTMLElement* tbody = Traversal<HTMLElement>::firstChild(*table, HasHTMLTagName(tbodyTag)); tbody; tbody = Traversal<HTMLElement>::nextSibling(*tbody, HasHTMLTagName(tbodyTag))) {
+        for (HTMLTableRowElement* row = Traversal<HTMLTableRowElement>::firstChild(*tbody); row; row = Traversal<HTMLTableRowElement>::nextSibling(*row)) {
+            if (row == this)
+                return rIndex;
+            ++rIndex;
         }
     }