Make item and namedItem args in MimeTypeArray/PluginArray/Plugin non-optional

third_party/WebKit/Source/modules/plugins/MimeTypeArray.idl

Index: third_party/WebKit/Source/modules/plugins/MimeTypeArray.idl
diff --git a/third_party/WebKit/Source/modules/plugins/MimeTypeArray.idl b/third_party/WebKit/Source/modules/plugins/MimeTypeArray.idl
index 9854da4f32dd14426342ce700d678642db08438c..ef3d6b722c2d0591d60ca0ab222eaee2454e0a6e 100644
--- a/third_party/WebKit/Source/modules/plugins/MimeTypeArray.idl
+++ b/third_party/WebKit/Source/modules/plugins/MimeTypeArray.idl
@@ -22,7 +22,7 @@
     ImplementedAs=DOMMimeTypeArray
 ] interface MimeTypeArray {
     readonly attribute unsigned long length;
-    getter MimeType item([Default=Undefined] optional unsigned long index);
-    MimeType namedItem([Default=Undefined] optional DOMString name);
-    [NotEnumerable, ImplementedAs=namedItem] getter MimeType ([Default=Undefined] optional DOMString name);
+    getter MimeType? item(unsigned long index);
+    MimeType? namedItem(DOMString name);
+    [NotEnumerable, ImplementedAs=namedItem] getter MimeType? (DOMString name);
 };