select.add() should support optgroup adding and before index

Source/core/html/HTMLOptionsCollection.cpp

Index: Source/core/html/HTMLOptionsCollection.cpp
diff --git a/Source/core/html/HTMLOptionsCollection.cpp b/Source/core/html/HTMLOptionsCollection.cpp
index d1abb1d3c23f1a98665710f3e1f94e168b1186e2..4a37c0ab0a6a4aedd5678cdf123ffbe247499d6a 100644
--- a/Source/core/html/HTMLOptionsCollection.cpp
+++ b/Source/core/html/HTMLOptionsCollection.cpp
@@ -93,7 +93,7 @@ void HTMLOptionsCollection::add(PassRefPtr<HTMLOptionElement> element, int index
     if (index == -1 || unsigned(index) >= length())
         select.add(newOption, 0, exceptionState);
     else
-        select.add(newOption, toHTMLOptionElement(item(index)), exceptionState);
+        select.addBeforeOptionAtIndex(newOption, unsigned(index), exceptionState);

[tkent, 2014/03/27 06:13:35]

Do not use C-style cast.

[keishi, 2014/03/27 06:52:03]

Done.

 
     ASSERT(!exceptionState.hadException());
 }