Make RootScroller set the outer viewport scroll layer in the compositor

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 61 matching lines @@
 #include "core/layout/compositing/PaintLayerCompositor.h"
 #include "core/layout/svg/LayoutSVGRoot.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
 #include "core/page/AutoscrollController.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/FocusController.h"
 #include "core/page/FrameTree.h"
 #include "core/page/Page.h"
 #include "core/page/scrolling/ChildViewportScrollCallback.h"
+#include "core/page/scrolling/RootScrollerController.h"
 #include "core/page/scrolling/RootViewportScrollCallback.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/paint/FramePainter.h"
 #include "core/paint/PaintLayer.h"
 #include "core/paint/PrePaintTreeWalk.h"
 #include "core/plugins/PluginView.h"
 #include "core/style/ComputedStyle.h"
 #include "core/svg/SVGDocumentExtensions.h"
 #include "core/svg/SVGSVGElement.h"
 #include "platform/Histogram.h"
@@ skipping 2448 matching lines @@
 
             DCHECK(lifecycle().state() >= DocumentLifecycle::CompositingClean);
 
             if (targetState >= DocumentLifecycle::PrePaintClean) {
                 if (!RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled())
                     invalidateTreeIfNeededRecursive();
 
                 if (view.compositor()->inCompositingMode())
                     scrollingCoordinator()->updateAfterCompositingChangeIfNeeded();
 
+                m_frame->document()->rootScrollerController()->didUpdateCompositing();
                 updateCompositedSelectionIfNeeded();
             }
         }
 
         if (targetState >= DocumentLifecycle::PrePaintClean) {
             if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
                 updatePaintProperties();
         }
 
         if (targetState == DocumentLifecycle::PaintClean) {
@@ skipping 1686 matching lines @@
     return m_subtreeThrottled || (m_hiddenForThrottling && m_crossOriginForThrottling);
 }
 
 LayoutBox& FrameView::boxForScrollControlPaintInvalidation() const
 {
     ASSERT(!layoutViewItem().isNull());
     return *layoutView();
 }
 
 } // namespace blink