^^ that'll be a nice addition, thanks.
As for OS testing 
Windows : 
 - Chrome :+1: 
 - Firefox 19 :+1: 
 - Maxthon :+1: 
 - Safari :-1: 
 - Opera :-1: 

Linux : 
 - Chromium :+1: 
 - Firefox :+1: 

Mac OSX : 
 - Chrome :+1: 
 - Safari :-1:

iOS 6.0 ( on simulator ) :
 - Safari :-1: 

Android 4.2.2 :
 - Embeded web browser & Chrome :-1: (Blob support is present but doesn't work it launches a download and loops)
 - Maxthon :-1: 
 - Firefox (partially works downloads the file with .part extension at the end and adobe acrobat can't read it)

I think you should test for Safari & Opera and redirect to the dataurlnewwindow in that case.