Chromium's Rietveld's instance is using about 100 MB of storage a week, and 
I'm looking at reducing that.

One thing I'm looking at it is reusing base files when they're the same as 
earlier patchsets.  This doesn't affect Rietveld's UI.

One other idea though is to remove the "Download" beside each file.  I 
don't think it's needed, since if someone wants to apply a patch they will 
most probably want to apply it to all the files.  If someone really wants 
to do it to just one file, then they can edit the full patch themself.  Are 
people ok with this change?