[gnome-calculator] Remove unused function

[Robert Roth <robertroth src gnome org>]

commit 1a84e471e8f33fd4a477436c82bd28d804cd2ba4
Author: Robert Roth <robert roth off gmail com>
Date:   Mon Jan 20 00:08:18 2020 +0200

    Remove unused function

 src/math-display.vala | 12 ------------
 1 file changed, 12 deletions(-)
---
diff --git a/src/math-display.vala b/src/math-display.vala
index 8719dda2..e420029d 100644
--- a/src/math-display.vala
+++ b/src/math-display.vala
@@ -139,18 +139,6 @@ public class MathDisplay : Gtk.Viewport
         }
     }
 
-    private bool function_completion_window_visible ()
-    {
-        unowned List<Gtk.SourceCompletionProvider> providers_list = source_view.get_completion 
().get_providers ();
-        if (providers_list.length () > 0)
-        {
-            MathFunction[] functions = FunctionCompletionProvider.get_matches_for_completion_at_cursor 
(equation);
-            string[] variables = VariableCompletionProvider.get_matches_for_completion_at_cursor (equation, 
equation.variables);
-            return ((functions.length > 0 || variables.length > 0) ? true : false);
-        }
-        return false;
-    }
-
     protected override bool key_press_event (Gdk.EventKey event)
     {
         return source_view.key_press_event (event);