Use ScrollAnchor in FrameView and PaintLayerScrollableArea.

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 28 matching lines @@
  * other provisions required by the MPL or the GPL, as the case may be.
  * If you do not delete the provisions above, a recipient may use your
  * version of this file under any of the LGPL, the MPL or the GPL.
  */
 
 #ifndef PaintLayerScrollableArea_h
 #define PaintLayerScrollableArea_h
 
 #include "core/CoreExport.h"
 #include "core/layout/LayoutBox.h"
+#include "core/layout/ScrollAnchor.h"
 #include "core/paint/PaintInvalidationCapableScrollableArea.h"
 #include "core/paint/PaintLayerFragment.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 enum ResizerHitTestType {
     ResizerForPointer,
     ResizerForTouch
 };
@@ skipping 264 matching lines @@
 
     LayoutScrollbarPart* resizer() const override { return m_resizer; }
 
     const IntPoint& cachedOverlayScrollbarOffset() { return m_cachedOverlayScrollbarOffset; }
     void setCachedOverlayScrollbarOffset(const IntPoint& offset) { m_cachedOverlayScrollbarOffset = offset; }
 
     IntRect rectForHorizontalScrollbar(const IntRect& borderBoxRect) const;
     IntRect rectForVerticalScrollbar(const IntRect& borderBoxRect) const;
 
     Widget* widget() override;
+    ScrollAnchor& scrollAnchor() { return m_scrollAnchor; }
     bool isPaintLayerScrollableArea() const override { return true; }
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     explicit PaintLayerScrollableArea(PaintLayer&);
 
     bool hasHorizontalOverflow() const;
     bool hasVerticalOverflow() const;
     bool hasScrollableHorizontalOverflow() const;
@@ skipping 21 matching lines @@
     void updateResizerStyle();
 
 
     void updateScrollableAreaSet(bool hasOverflow);
 
     void updateCompositingLayersAfterScroll();
 
     // PaintInvalidationCapableScrollableArea
     LayoutBox& boxForScrollControlPaintInvalidation() const { return box(); }
 
+    bool scrollAnchoringEnabled() const;
+
     PaintLayer& m_layer;
 
     // Keeps track of whether the layer is currently resizing, so events can cause resizing to start and stop.
     unsigned m_inResizeMode : 1;
     unsigned m_scrollsOverflow : 1;
 
     unsigned m_inOverflowRelayout : 1;
 
     PaintLayer* m_nextTopmostScrollChild;
     PaintLayer* m_topmostScrollChild;
@@ skipping 15 matching lines @@
     DoubleSize m_scrollOffset;
 
     IntPoint m_cachedOverlayScrollbarOffset;
 
     // LayoutObject to hold our custom scroll corner.
     LayoutScrollbarPart* m_scrollCorner;
 
     // LayoutObject to hold our custom resizer.
     LayoutScrollbarPart* m_resizer;
 
+    ScrollAnchor m_scrollAnchor;
+
 #if ENABLE(ASSERT)
     bool m_hasBeenDisposed;
 #endif
 };
 
 DEFINE_TYPE_CASTS(PaintLayerScrollableArea, ScrollableArea, scrollableArea,
     scrollableArea->isPaintLayerScrollableArea(),
     scrollableArea.isPaintLayerScrollableArea());
 
 } // namespace blink
 
 #endif // LayerScrollableArea_h