Remove ScrollableArea::GetFrameViewBase and move ScheduleAnimation into subclasses.

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 409 matching lines @@
   const IntPoint& CachedOverlayScrollbarOffset() {
     return cached_overlay_scrollbar_offset_;
   }
   void SetCachedOverlayScrollbarOffset(const IntPoint& offset) {
     cached_overlay_scrollbar_offset_ = offset;
   }
 
   IntRect RectForHorizontalScrollbar(const IntRect& border_box_rect) const;
   IntRect RectForVerticalScrollbar(const IntRect& border_box_rect) const;
 
-  FrameViewBase* GetFrameViewBase() override;
+  bool ScheduleAnimation() override;
   bool ShouldPerformScrollAnchoring() const override;
   ScrollAnchor* GetScrollAnchor() override { return &scroll_anchor_; }
   bool IsPaintLayerScrollableArea() const override { return true; }
 
   LayoutBox* GetLayoutBox() const override { return &Box(); }
 
   FloatQuad LocalToVisibleContentQuad(const FloatQuad&,
                                       const LayoutObject*,
                                       unsigned = 0) const final;
 
@@ skipping 163 matching lines @@
 
 DEFINE_TYPE_CASTS(PaintLayerScrollableArea,
                   ScrollableArea,
                   scrollableArea,
                   scrollableArea->IsPaintLayerScrollableArea(),
                   scrollableArea.IsPaintLayerScrollableArea());
 
 }  // namespace blink
 
 #endif  // LayerScrollableArea_h