[root layer scrolls] TopDocumentRootScrollerController needs to use layoutViewportScrollableArea

third_party/WebKit/Source/core/page/scrolling/TopDocumentRootScrollerController.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/page/scrolling/TopDocumentRootScrollerController.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/PageScaleConstraintsSet.h"
@@ skipping 51 matching lines @@
 IntSize TopDocumentRootScrollerController::RootScrollerVisibleArea() const {
   if (!TopDocument() || !TopDocument()->View())
     return IntSize();
 
   float minimum_page_scale =
       page_->GetPageScaleConstraintsSet().FinalConstraints().minimum_scale;
   int browser_controls_adjustment =
       ceilf(page_->GetVisualViewport().BrowserControlsAdjustment() /
             minimum_page_scale);
 
-  return TopDocument()->View()->VisibleContentSize(kExcludeScrollbars) +
+  return TopDocument()
+             ->View()
+             ->LayoutViewportScrollableArea()
+             ->VisibleContentRect(kExcludeScrollbars)
+             .Size() +
          IntSize(0, browser_controls_adjustment);
 }
 
 Element* TopDocumentRootScrollerController::FindGlobalRootScrollerElement() {
   if (!TopDocument())
     return nullptr;
 
   Node* effective_root_scroller =
       &TopDocument()->GetRootScrollerController().EffectiveRootScroller();
 
@@ skipping 140 matching lines @@
 
 PaintLayer* TopDocumentRootScrollerController::RootScrollerPaintLayer() const {
   return RootScrollerUtil::PaintLayerForRootScroller(global_root_scroller_);
 }
 
 Element* TopDocumentRootScrollerController::GlobalRootScroller() const {
   return global_root_scroller_.Get();
 }
 
 }  // namespace blink