chrome: Ignore minimized windows when updating visibility

The current check for fullscreen windows ignores the window's
minimization state, so that chrome which is hidden in fullscreen
will always hide if the window on top of the window stack is
fullscreen, even if it is actually minimized.
Instead, skip minimized windows when looking for fullscreen windows.

https://bugzilla.gnome.org/show_bug.cgi?id=655446

js/ui/chrome.js

@@ -289,6 +289,11 @@ Chrome.prototype = {
 
         for (let i = windows.length - 1; i > -1; i--) {
             let window = windows[i];
+
+            // Skip minimized windows
+            if (!window.showing_on_its_workspace())
+                continue;
+
             let layer = window.get_meta_window().get_layer();
 
             if (layer == Meta.StackLayer.FULLSCREEN) {