[gnome-shell/wip/exalm/gestures: 38/38] tmp: Throttle SwipeTracker updates

[Alexander Mikhaylenko <alexm src gnome org>]

commit e7ceffffc440f9926574c7fea67a6b766a7e4870
Author: Alexander Mikhaylenko <exalm7659 gmail com>
Date:   Mon Jul 8 14:31:07 2019 +0500

    tmp: Throttle SwipeTracker updates
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/605

 js/ui/swipeTracker.js | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
---
diff --git a/js/ui/swipeTracker.js b/js/ui/swipeTracker.js
index c876fd2f5..cd127ebe9 100644
--- a/js/ui/swipeTracker.js
+++ b/js/ui/swipeTracker.js
@@ -266,6 +266,8 @@ var SwipeTracker = class {
             scrollGesture.connect('update', this._updateGesture.bind(this));
             scrollGesture.connect('end', this._endGesture.bind(this));
         }
+
+        this._prevUpdate = 0;
     }
 
     get enabled() {
@@ -334,7 +336,13 @@ var SwipeTracker = class {
 
         // Clamp progress to [0,1]
         let progress = this._progress / (1 + (this._progress > 0 ? this._backExtent : this._forwardExtent) / 
this._distance);
-        this.emit('update', progress);
+
+        if (this._prevUpdate != 0)
+            Meta.later_remove(this._prevUpdate);
+        this._prevUpdate = Meta.later_add(Meta.LaterType.BEFORE_REDRAW, () => {
+            this.emit('update', progress);
+            this._prevUpdate = 0;
+        });
 
         this._prevTime = time;
     }