Remove TreatNullAs=NullString for HTMLMetaElement

Source/core/html/HTMLMetaElement.idl

Index: Source/core/html/HTMLMetaElement.idl
diff --git a/Source/core/html/HTMLMetaElement.idl b/Source/core/html/HTMLMetaElement.idl
index 8149993594551d48c6bd1db093fad375ace2b2bc..41d369e22ca5129df62fea8fb45e6305fd66fe26 100644
--- a/Source/core/html/HTMLMetaElement.idl
+++ b/Source/core/html/HTMLMetaElement.idl
@@ -18,9 +18,8 @@
  */
 
 interface HTMLMetaElement : HTMLElement {
-    [Reflect, TreatNullAs=NullString] attribute DOMString content;
-    [Reflect=http_equiv, TreatNullAs=NullString] attribute DOMString httpEquiv;
-    [Reflect, TreatNullAs=NullString] attribute DOMString name;
-    [Reflect, TreatNullAs=NullString] attribute DOMString scheme;
+    [Reflect] attribute DOMString content;
+    [Reflect=http_equiv] attribute DOMString httpEquiv;
+    [Reflect] attribute DOMString name;
+    [Reflect] attribute DOMString scheme;
 };
-