Add support for Downlevel-revealed Conditional Comments

Marked #860828: Add support for non-IE browsers as a duplicate of this one.

How would one do this for the Drupal 7 version where there is no "conditional_styles.theme.inc" to modify?

Here's a patch that does (presumably) the same thing for Drupal 7. If your stylesheets-conditional declaration in your .info file contains the string "!IE" then it will generate a conditional style that is loaded for all other browsers except IE. If you use a conditional like this, you can add CSS for both newer versions of IE and all non-IE browsers:

stylesheets-conditional[(gte IE 9)|(gt IEMobile 7)|(!IE)][all][] = css/style.css

This will result in output like this:

<!--[if (gte IE 9)|(gt IEMobile 7)|(!IE)]><!-->
<style>@import url("http://example.com/sites/all/themes/example/css/style.css?mf27lk");</style>
<!--<![endif]-->

Which basically means, "If this browser is a new version of IE, or not IE at all" load this content. The closing comment <!--> ensures this stylesheet gets added by non-IE browsers which don't understand conditional comments. Since Drupal core supports this functionality, the patch is quite trivial. We'll just need to update our documentation to explain how this functionality works.

I didn't even know the test bot would test these. Manually testing now.

#3: conditional_styles_not_ie-580440.patch queued for re-testing.

Fixed in 7.x-2.x.