Revert of Remove indirection: setup scrollbar scroll layers in the scrollbar constructor

third_party/WebKit/Source/core/frame/VisualViewport.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 26 matching lines @@
 #include "platform/geometry/FloatSize.h"
 #include "platform/geometry/IntSize.h"
 #include "platform/graphics/GraphicsLayerClient.h"
 #include "platform/scroll/ScrollableArea.h"
 #include "public/platform/WebScrollbar.h"
 #include "public/platform/WebSize.h"
 #include <memory>
 
 namespace blink {
 class WebScrollbarLayer;
+class WebLayer;
 }
 
 namespace blink {
 
 class FrameHost;
 class GraphicsContext;
 class GraphicsLayer;
 class IntRect;
 class IntSize;
 class LocalFrame;
@@ skipping 55 matching lines @@
   // Sets scale and location in one operation, preventing intermediate clamping.
   void setScaleAndLocation(float scale, const FloatPoint& location);
   void setScale(float);
   float scale() const { return m_scale; }
 
   // Update scale factor, magnifying or minifying by magnifyDelta, centered
   // around the point specified by anchor in window coordinates. Returns false
   // if page scale factor is left unchanged.
   bool magnifyScaleAroundAnchor(float magnifyDelta, const FloatPoint& anchor);
 
+  void setScrollLayerOnScrollbars(WebLayer*) const;
+
   // The portion of the unzoomed frame visible in the visual viewport,
   // in partial CSS pixels. Relative to the main frame.
   FloatRect visibleRect() const;
 
   // The viewport rect relative to the document origin, in partial CSS pixels.
   FloatRect visibleRectInDocument() const;
 
   // Convert the given rect in the main FrameView's coordinates into a rect
   // in the viewport. The given and returned rects are in CSS pixels, meaning
   // scale isn't applied.
@@ skipping 130 matching lines @@
   float m_scale;
   IntSize m_size;
   float m_browserControlsAdjustment;
   float m_maxPageScale;
   bool m_trackPinchZoomStatsForPage;
 };
 
 }  // namespace blink
 
 #endif  // VisualViewport_h