[binding] Replace [CustomIndexedGetter] attributes with [Custom] getter

Source/core/css/StyleSheetList.idl

Index: Source/core/css/StyleSheetList.idl
diff --git a/Source/core/css/StyleSheetList.idl b/Source/core/css/StyleSheetList.idl
index 84224dfb31a17c026a8e71fe8263910c30bfc1fd..b4681abda243bf42fbb0fc315d4d475b5ac71f07 100644
--- a/Source/core/css/StyleSheetList.idl
+++ b/Source/core/css/StyleSheetList.idl
@@ -21,9 +21,9 @@
 // Introduced in DOM Level 2:
 [
     GenerateIsReachable=document,
-    CustomNamedGetter
 ] interface StyleSheetList {
     readonly attribute unsigned long    length;
     getter StyleSheet         item([Default=Undefined] optional unsigned long index);
+    [Custom] getter StyleSheet (DOMString name);
 };