Pass integer scroll position to CC if frameView has non-layered viewport constrained objects

Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
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 }
 
 LayoutRect FrameView::viewportConstrainedVisibleContentRect() const
 {
     LayoutRect viewportRect = visibleContentRect();
     // Ignore overhang. No-op when not using rubber banding.
     viewportRect.setLocation(clampScrollPosition(scrollPosition()));
     return viewportRect;
 }
 
+bool FrameView::hasVisibleViewportConstrainedObjects() const
+{
+    const ViewportConstrainedObjectSet* objects = viewportConstrainedObjects();
+    if (!objects)
+        return false;
+    for (const RenderObject* renderer : *objects) {
+        RenderLayer* layer = toRenderBoxModelObject(renderer)->layer();
+        if (layer) {
+            layer->updateDescendantDependentFlags();
+            if (!layer->subtreeIsInvisible())
+                return true;
+        }
+    }
+    return false;
+}
+
 void FrameView::viewportConstrainedVisibleContentSizeChanged(bool widthChanged, bool heightChanged)
 {
     if (!hasViewportConstrainedObjects())
         return;
 
     // If viewport is not enabled, frameRect change will cause layout size change and then layout.
     // Otherwise, viewport constrained objects need their layout flags set separately to ensure
     // they are positioned correctly. In the virtual-viewport pinch mode frame rect changes wont
     // necessarily cause a layout size change so only take this early-out if we're in old-style
     // pinch.
@@ skipping 2681 matching lines @@
         return;
 
     ScrollableArea::setScrollOrigin(origin);
 
     // Update if the scroll origin changes, since our position will be different if the content size did not change.
     if (updatePositionAtAll && updatePositionSynchronously)
         updateScrollbars(scrollOffsetDouble());
 }
 
 } // namespace blink