[mutter] cursor-tracker: Only emit 'cursor-moved' if it moved

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit b24b95db15c84284e7f628eb336010fc0e690403
Author: Jonas Ådahl <jadahl gmail com>
Date:   Wed Jul 29 11:20:21 2020 +0200

    cursor-tracker: Only emit 'cursor-moved' if it moved
    
    This makes it safe to update the position with the same coordinates
    without risking 'cursor-moved' being emitted when nothing actually
    moved.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1391

 src/backends/meta-cursor-tracker.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)
---
diff --git a/src/backends/meta-cursor-tracker.c b/src/backends/meta-cursor-tracker.c
index 39f6b2b007..f9331b6f62 100644
--- a/src/backends/meta-cursor-tracker.c
+++ b/src/backends/meta-cursor-tracker.c
@@ -62,6 +62,9 @@ typedef struct _MetaCursorTrackerPrivate
 
   gboolean is_showing;
 
+  float x;
+  float y;
+
   MetaCursorSprite *effective_cursor; /* May be NULL when hidden */
   MetaCursorSprite *displayed_cursor;
 
@@ -179,6 +182,8 @@ meta_cursor_tracker_init (MetaCursorTracker *tracker)
     meta_cursor_tracker_get_instance_private (tracker);
 
   priv->is_showing = TRUE;
+  priv->x = -1.0;
+  priv->y = -1.0;
 }
 
 static void
@@ -484,12 +489,25 @@ meta_cursor_tracker_update_position (MetaCursorTracker *tracker,
     meta_cursor_tracker_get_instance_private (tracker);
   MetaCursorRenderer *cursor_renderer =
     meta_backend_get_cursor_renderer (priv->backend);
+  gboolean position_changed;
 
   g_assert (meta_is_wayland_compositor ());
 
+  if (priv->x != new_x || priv->y != new_y)
+    {
+      position_changed = TRUE;
+      priv->x = new_x;
+      priv->y = new_y;
+    }
+  else
+    {
+      position_changed = FALSE;
+    }
+
   meta_cursor_renderer_set_position (cursor_renderer, new_x, new_y);
 
-  g_signal_emit (tracker, signals[CURSOR_MOVED], 0, new_x, new_y);
+  if (position_changed)
+    g_signal_emit (tracker, signals[CURSOR_MOVED], 0, new_x, new_y);
 }
 
 static void