title: Where is ContentWidget.CwConstants located and what is it?
body: <p>I´ve just started learning GWT and I´m trying to implement <a href="http://gwt.google.com/samples/Showcase/Showcase.html#!CwFileUpload" rel="nofollow noreferrer">http://gwt.google.com/samples/Showcase/Showcase.html#!CwFileUpload</a> and but failing miserably.</p>
  
  <p>Where is the ContentWidget.CwConstants suppose to come from and what exactly is it?</p>
  
  <pre><code>public static interface CwConstants extends Constants,
        ContentWidget.CwConstants {
      String cwFileUploadButton();
  
      String cwFileUploadDescription();
  
      String cwFileUploadName();
  
  String cwFileUploadNoFileError();
  
  String cwFileUploadSelectFile();
  
      String cwFileUploadSuccessful();
    }
  </code></pre>