Windows ICO format should be gzipped

[GoogleCodeExporter]

Windows' icon file format is not internally compressed, and should be gzipped 
when served. wpt is not currently checking for this.

There are various MIME types in use for this format, and the official one 
registered by Microsoft doesn't work in Internet Explorer (are we surprised?) 
prior to IE9. See http://en.wikipedia.org/wiki/ICO_%28file_format%29#MIME_type

wpt should look for at least the most common, image/x-icon and the official 
one. Microsoft Icon format images served with other mime types should generate 
an error/warning.

Original issue reported on code.google.com by nicksha...@gmail.com on 25 Sep 2012 at 7:25

[GoogleCodeExporter]

This issue was closed by revision r1511.

Original comment by PatMee...@gmail.com on 25 Sep 2012 at 3:22

• Changed state: Fixed

[GoogleCodeExporter]

I don't think checking for such a short string as mime.Find(_T(".icon")) is 
going to work: almost all other image formats used on the web are internally 
compressed (SVG, XBM and XPM are not, as those are ASCII-based image formats, 
and so should be gzipped too; BMP isn't compressed, but that shouldn't be used 
anyway)

Original comment by nicksha...@gmail.com on 25 Sep 2012 at 3:35

[GoogleCodeExporter]

Also, according to that Wikipaedia article, modern ICO files can contain PNG 
data (I did not know this!) rather than wrap BMP images of different pixel 
sizes. This is unlikely to be the case for standard 16/32px favicons but as 
screen resolutions go up and favicons are used at higher width/heights/dpi by 
UAs and OSes (think putting website link on phone home screen) people might 
start using the (mostly-compressed) PNG-file-with-ICO-header format. Gzipping 
such files might be redundant.

Original comment by nicksha...@gmail.com on 25 Sep 2012 at 3:42