HTMLTableRowElement.insertCell()'s argument default value should be -1

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 d6fd9cefc8fe7f4f2adeddf0c77c22868c22e1aa..0e63ab98b32b7f910982630962dcb6ad32f9e0d5 100644
--- a/Source/core/html/HTMLTableRowElement.cpp
+++ b/Source/core/html/HTMLTableRowElement.cpp
@@ -119,6 +119,12 @@ int HTMLTableRowElement::sectionRowIndex() const
     return rIndex;
 }
 
+PassRefPtr<HTMLElement> HTMLTableRowElement::insertCell(ExceptionState& exceptionState)
+{
+    // The default 'index' argument value is -1.
+    return insertCell(-1, exceptionState);
+}
+
 PassRefPtr<HTMLElement> HTMLTableRowElement::insertCell(int index, ExceptionState& exceptionState)
 {
     RefPtr<HTMLCollection> children = cells();