Let depending applications use gstreamer plugins webkit depends on

svn path=/nixpkgs/trunk/; revision=16548

pkgs/development/libraries/webkit/default.nix

@@ -55,4 +55,7 @@ rec {
   meta = {
     description = "WebKit - a fast and correct HTML renderer";
   };
+  passthru = {
+    inherit gstreamer gstPluginsBase gstPluginsGood gstFfmpeg;
+  };
 }