Blink Compositor Animation: Introduce CompositorAnimationHost correctly.

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

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights
    reserved.
 
    This library is free software; you can redistribute it and/or
@@ skipping 423 matching lines @@
   PaintLayer* layer() const override;
   GraphicsLayer* layerForScrolling() const override;
   GraphicsLayer* layerForHorizontalScrollbar() const override;
   GraphicsLayer* layerForVerticalScrollbar() const override;
   GraphicsLayer* layerForScrollCorner() const override;
   int scrollSize(ScrollbarOrientation) const override;
   bool isScrollCornerVisible() const override;
   bool userInputScrollable(ScrollbarOrientation) const override;
   bool shouldPlaceVerticalScrollbarOnLeft() const override;
   Widget* getWidget() override;
+  CompositorAnimationHost* compositorAnimationHost() const override;
   CompositorAnimationTimeline* compositorAnimationTimeline() const override;
   LayoutBox* layoutBox() const override;
   FloatQuad localToVisibleContentQuad(const FloatQuad&,
                                       const LayoutObject*,
                                       unsigned = 0) const final;
 
   LayoutRect scrollIntoView(const LayoutRect& rectInContent,
                             const ScrollAlignment& alignX,
                             const ScrollAlignment& alignY,
                             ScrollType = ProgrammaticScroll) override;
@@ skipping 730 matching lines @@
                   widget.isFrameView());
 DEFINE_TYPE_CASTS(FrameView,
                   ScrollableArea,
                   scrollableArea,
                   scrollableArea->isFrameView(),
                   scrollableArea.isFrameView());
 
 }  // namespace blink
 
 #endif  // FrameView_h