[RootLayerScrolls] Fix frame scrolling layer in ScrollingCoordinator

third_party/WebKit/LayoutTests/scrollingcoordinator/resources/non-fast-scrollable-region-testing.js

 // setMockScrollbarsEnabled doesn't actually invalidate scrollbars
 // so if we don't set it immediately, they won't repaint/relayout
 // correctly!  http://crbug.com/365509
 if (window.internals)
     window.internals.settings.setMockScrollbarsEnabled(true);
 
 // Draws green overlays for non-fast scrollable regions. This provides a visual
 // feedback that is useful when running the test interactively.
 function drawNonFastScrollableRegionOverlays() {
     var overlay = document.createElement("div");
@@ skipping 16 matching lines @@
         overlay.appendChild(patch);
     }
 
     document.body.appendChild(overlay);
 }
 
 function rectToString(rect) {
     return '[' + [rect.left, rect.top, rect.width, rect.height].join(', ') + ']';
 }
 
+function sortRects(rects) {
+  Array.prototype.sort.call(rects, (a, b) => (
+      a.left - b.left ||
+      a.top - b.top ||
+      a.width - b.width ||
+      a.height - b.height));
+  return rects;
+}