Right now, some icons exist while many don’t. This may confuse users with sight problems and generally make using Gnome very difficult for some people.
Every module that installs an application launcher is of course affected by this goal. There are many icons that are already done (that are not shown on the below screenshot), and quite a few to be done before Gnome 3.8
This isn’t official!
Please note that this is just a proposal for the time being and it is not yet sure that it will become an official Gnome goal. Check this Gnome Live webpage for more information and news about high contrast application icons.