Fix paint code so that overlays and views paint their own layers.

third_party/WebKit/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.
  *
@@ skipping 2421 matching lines @@
     ASSERT(frame() == page()->mainFrame() || (!frame().tree().parent()->isLocalFrame()));
 
     LayoutView* view = layoutView();
     ASSERT(view);
     forAllNonThrottledFrameViews([](FrameView& frameView) { frameView.lifecycle().advanceTo(DocumentLifecycle::InPaint); });
 
     // A null graphics layer can occur for painting of SVG images that are not parented into the main frame tree,
     // or when the FrameView is the main frame view of a page overlay. The page overlay is in the layer tree of
     // the host page and will be painted during synchronized painting of the host page.
     if (GraphicsLayer* rootGraphicsLayer = view->compositor()->rootGraphicsLayer()) {
-        // Find the real root GraphicsLayer because we also need to paint layers not under the root graphics layer of
-        // the LayoutView, e.g. scrollbar layers created by PaintLayerCompositor and VisualViewport.
-        // We could ask PaintLayerCompositor and VisualViewport for the real root GraphicsLayer, but the following loop
-        // has the least dependency to those things which might change for slimming paint v2.
-        while (GraphicsLayer* parent = rootGraphicsLayer->parent())
-            rootGraphicsLayer = parent;
         synchronizedPaintRecursively(rootGraphicsLayer);
     }
+    if (GraphicsLayer* layerForHorizontalScrollbar = view->compositor()->layerForHorizontalScrollbar()) {
+        synchronizedPaintRecursively(layerForHorizontalScrollbar);
+    }
+    if (GraphicsLayer* layerForVerticalScrollbar = view->compositor()->layerForVerticalScrollbar()) {
+        synchronizedPaintRecursively(layerForVerticalScrollbar);
+    }
+    if (GraphicsLayer* layerForScrollCorner = view->compositor()->layerForScrollCorner()) {
+        synchronizedPaintRecursively(layerForScrollCorner);
+    }
 
     forAllNonThrottledFrameViews([](FrameView& frameView) {
         frameView.lifecycle().advanceTo(DocumentLifecycle::PaintClean);
         frameView.layoutView()->layer()->clearNeedsRepaintRecursively();
     });
 }
 
 void FrameView::synchronizedPaintRecursively(GraphicsLayer* graphicsLayer)
 {
     if (graphicsLayer->drawsContent())
@@ skipping 1546 matching lines @@
     return m_hiddenForThrottling && m_crossOriginForThrottling;
 }
 
 LayoutBox& FrameView::boxForScrollControlPaintInvalidation() const
 {
     ASSERT(layoutView());
     return *layoutView();
 }
 
 } // namespace blink