Drop support for [TreatUndefinedAs=NullString]

third_party/WebKit/Source/core/frame/History.idl

Index: third_party/WebKit/Source/core/frame/History.idl
diff --git a/third_party/WebKit/Source/core/frame/History.idl b/third_party/WebKit/Source/core/frame/History.idl
index 54e643c594d94d09f5270a70dc3066b4da42dea9..fef8e1fdbaa62510270b50b6b93da475f753e3eb 100644
--- a/third_party/WebKit/Source/core/frame/History.idl
+++ b/third_party/WebKit/Source/core/frame/History.idl
@@ -36,7 +36,7 @@ interface History {
     [CallWith=ExecutionContext] void back();
     [CallWith=ExecutionContext] void forward();
     // TODO(foolip): The SerializedScriptValue types should be any.
-    // TODO(foolip): The title arguments should simply be 'DOMString title'.
-    [RaisesException] void pushState(SerializedScriptValue data, [TreatUndefinedAs=NullString] DOMString? title, optional DOMString? url = null);
-    [RaisesException] void replaceState(SerializedScriptValue data, [TreatUndefinedAs=NullString] DOMString? title, optional DOMString? url = null);
+    // TODO(foolip): The title arguments should not be nullable.
+    [RaisesException] void pushState(SerializedScriptValue data, DOMString? title, optional DOMString? url = null);
+    [RaisesException] void replaceState(SerializedScriptValue data, DOMString? title, optional DOMString? url = null);
 };