The contextId argument for HTMLCanvasElement getContext() api should not be optional

Source/core/html/HTMLCanvasElement.idl

 /*
  * Copyright (C) 2006, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 27 matching lines @@
     // The PermissiveDictionaryConversion extended attribute is needed to allow the
     // autogenerated code to match the behavior of the custom binding. Web IDL
     // requires throwing TypeError if the incoming argument is not an object type
     // (and is not undefined or null). The binding must ignore this.
     //
     // Also note: the only reason this must return type "any" is to allow the
     // InspectorInstrumentation wrappers to be called for canvases. If that could be
     // handled differently the return type could be changed to "RenderingContext?"
     // and the [CallWith=ScriptState] extended attribute removed.
     //
-    // FIXME: The contextId argument should not be optional.
-    [CallWith=ScriptState] any getContext([Default=Undefined] optional DOMString contextId, [PermissiveDictionaryConversion] optional CanvasContextCreationAttributes attributes);
+    [CallWith=ScriptState] any getContext(DOMString contextId, [PermissiveDictionaryConversion] optional CanvasContextCreationAttributes attributes);
 
     // Note: The arguments argument is variadic in the spec, but not here as
     // only one extra argument is actually used.
     // FIXME: type should not be nullable or have a default value.
     [RaisesException] DOMString toDataURL(optional DOMString? type = null, optional any arguments);
 };