Liferay Faces Alloy and Liferay Faces Bridge Impl both provide mechanisms for processing multipart/form-data requests. The implementations are both similar since they use commons-fileupload. The only differences are due to differences between the Portlet and Servlet environments. Instead of providing two implementations in different JARs, Util should provide a new feature that can process file upload requests. This feature could support the servlet environment by default (both commons-fileupload and Servlet 3.0+ Part APIs), but allow others (such as the Bridge) to plug in support for Portlet commons-fileupload and Portlet 3.0+ Part APIs.
The benefit of this refactor would be that the vast majority of file upload code would exist in Util with minor amounts in the Bridge. Then the Bridge, Alloy, and Clay could utilize the same API to access uploaded files in all environments.