Update #179: progress bar is a bit less beautiful but works in Chromium now

src/app/app.component.scss

@@ -44,13 +44,17 @@ button:focus {
         width: 25%;
         height: 4px;
         background-color: mat-color($accent);
-        animation: 2s scroll linear infinite;
+        animation: 1.5s scroll linear infinite;
     }
 }
 
 @keyframes scroll {
-    from { transform: translateX(-100%); }
-    to { transform: translateX(400%); }
+    from { transform: translateX(-100px); }
+    to { transform: translateX(1000px); }
+    // units in % give a better result but freeze during
+    // synchronous function calls in Chromium (works in FF)
+    /* from { transform: translateX(-100%); }
+    to { transform: translateX(400%); } */
 }
 
 #open-menu {