All: Delegate to base _getCreateOptions().

[scottgonzalez]

Ensures that any extensions to the base widget will be handled properly by
individual widgets.

[jzaefferer]

Can we extend the common widget tests to make sure all _getCreateOptions overrides call _super?

Otherwise looks good.

[scottgonzalez]

That's tricky because we would need to create an instance of the widget to guarantee that the properties are set to reasonable values for the individual widget's implementation of _getCreateOptions(). Creating an instance requires knowing what markup to use, and widgets like checkboxradio don't have defaultElement set.

We can check for this._super() in the .toString() of ._getCreateOptions(), but it seems a little ghetto.

[jzaefferer]

I can't think of a non-ghetto approach to deal with this, so lets leave it as it is.