bool ScrollingCoordinator::hasNonLayerFixedObjects(FrameView* frameView) const { const FrameView::ViewportConstrainedObjectSet* viewportConstrainedObjects = frameView->viewportConstrainedObjects(); if (!viewportConstrainedObjects) return false; #if USE(ACCELERATED_COMPOSITING) for (FrameView::ViewportConstrainedObjectSet::const_iterator it = viewportConstrainedObjects->begin(), end = viewportConstrainedObjects->end(); it != end; ++it) { RenderObject* viewportConstrainedObject = *it; if (!viewportConstrainedObject->isBoxModelObject() || !viewportConstrainedObject->hasLayer()) return true; RenderBoxModelObject* viewportConstrainedBoxModelObject = toRenderBoxModelObject(viewportConstrainedObject); if (!viewportConstrainedBoxModelObject->layer()->backing()) return true; } return false; #else return viewportConstrainedObjects->size(); #endif }