Allow buttons to just be icons

Summary: Let's buttons just be an icon, no pressure to also have text.

Test Plan: UIExamples, Search, Home, Policy Controls... Probably 99% of them.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D18056

webroot/rsrc/js/phuix/PHUIXButtonView.js

@@ -102,6 +102,7 @@ JX.install('PHUIXButtonView', {
       }
 
       JX.DOM.alterClass(node, 'has-icon', !!icon);
+      JX.DOM.alterClass(node, 'has-text', !!text);
       JX.DOM.setContent(node, content);
     }
   }