[gnome-shell] windowManager: Discard workspace scroll smooth events

[Marge Bot <marge-bot src gnome org>]

commit 757e766a111d2babb0a693e6a07b2d06ab0499ae
Author: José Expósito <jose exposito89 gmail com>
Date:   Mon Aug 23 18:30:02 2021 +0200

    windowManager: Discard workspace scroll smooth events
    
    Since touchpad smooth scroll events with source finger are handled by
    the swipeTracker, the workspace scroll handler can focus on discrete
    events.
    
    Thanks to Mutter emulating discrete scroll events, see
    meta_seat_impl_notify_scroll_continuous_in_impl in meta-seat-impl.c,
    it is safe to ignore smooth scroll in the workspace scroll handler
    and handle exclusively discrete events.
    
    In addition, once high-resolution scroll events land in Mutter [1], a
    mouse will be able generate non emulated smooth scroll events that
    should be ignored in favour of the discrete scroll events.
    Otherwise, a single mouse wheel click will scroll through multiple
    workspaces at once.
    
    [1] https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1962
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1959>

 js/ui/windowManager.js | 19 ++-----------------
 1 file changed, 2 insertions(+), 17 deletions(-)
---
diff --git a/js/ui/windowManager.js b/js/ui/windowManager.js
index 48fa9a5934..c485fd0f99 100644
--- a/js/ui/windowManager.js
+++ b/js/ui/windowManager.js
@@ -1871,25 +1871,10 @@ var WindowManager = class {
         if (event.type() !== Clutter.EventType.SCROLL)
             return Clutter.EVENT_PROPAGATE;
 
-        if (event.is_pointer_emulated())
+        const direction = event.get_scroll_direction();
+        if (direction === Clutter.ScrollDirection.SMOOTH)
             return Clutter.EVENT_PROPAGATE;
 
-        let direction = event.get_scroll_direction();
-        if (direction === Clutter.ScrollDirection.SMOOTH) {
-            const [dx, dy] = event.get_scroll_delta();
-            if (Math.abs(dx) > Math.abs(dy)) {
-                direction = dx < 0
-                    ? Clutter.ScrollDirection.LEFT
-                    : Clutter.ScrollDirection.RIGHT;
-            } else if (Math.abs(dy) > Math.abs(dx)) {
-                direction = dy < 0
-                    ? Clutter.ScrollDirection.UP
-                    : Clutter.ScrollDirection.DOWN;
-            } else {
-                return Clutter.EVENT_PROPAGATE;
-            }
-        }
-
         const workspaceManager = global.workspace_manager;
         const vertical = workspaceManager.layout_rows === -1;
         const rtl = Clutter.get_default_text_direction() === Clutter.TextDirection.RTL;