Scrollbar no longer inherits from FrameViewBase.

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 453 matching lines @@
                             const ScrollAlignment& align_x,
                             const ScrollAlignment& align_y,
                             ScrollType = kProgrammaticScroll) override;
 
   // The window that hosts the FrameView. The FrameView will communicate scrolls
   // and repaints to the host window in the window's coordinate space.
   PlatformChromeClient* GetChromeClient() const;
 
   typedef HeapHashSet<Member<FrameViewBase>> ChildrenSet;
   typedef HeapHashSet<Member<PluginView>> PluginsSet;
+  typedef HeapHashSet<Member<Scrollbar>> ScrollbarsSet;
 
   // Functions for child manipulation and inspection.
   void SetParent(FrameViewBase*) override;
   void RemoveChild(FrameViewBase*);
   void AddChild(FrameViewBase*);
   const ChildrenSet* Children() const { return &children_; }
   void RemovePlugin(PluginView*);
   void AddPlugin(PluginView*);
   const PluginsSet* Plugins() const { return &plugins_; }
+  void RemoveScrollbar(Scrollbar*);
+  void AddScrollbar(Scrollbar*);
+  const ScrollbarsSet* Scrollbars() const { return &scrollbars_; }

[szager1, 2017/04/21 08:37:52]

Can this return a ScrollbarSet& instead?

[joelhockey, 2017/04/21 09:56:09]

Yes.  I will do a followup CL and I can make children, plugins and scrollbars
all be refs rather than pointers?

 
   // If the scroll view does not use a native widget, then it will have
   // cross-platform Scrollbars. These functions can be used to obtain those
   // scrollbars.
   Scrollbar* HorizontalScrollbar() const override {
     return scrollbar_manager_.HorizontalScrollbar();
   }
   Scrollbar* VerticalScrollbar() const override {
     return scrollbar_manager_.VerticalScrollbar();
   }
@@ skipping 502 matching lines @@
 
   AXObjectCache* AxObjectCache() const;
 
   void SetLayoutSizeInternal(const IntSize&);
 
   bool AdjustScrollbarExistence(ComputeScrollbarExistenceOption = kFirstPass);
   void AdjustScrollbarOpacity();
   void AdjustScrollOffsetFromUpdateScrollbars();
   bool VisualViewportSuppliesScrollbars();
 
-  bool IsFrameViewScrollbar(const FrameViewBase* child) const {
-    return HorizontalScrollbar() == child || VerticalScrollbar() == child;
-  }
-
   ScrollingCoordinator* GetScrollingCoordinator() const;
 
   void PrepareLayoutAnalyzer();
   std::unique_ptr<TracedValue> AnalyzerCounters();
 
   // LayoutObject for the viewport-defining element (see
   // Document::viewportDefiningElement).
   LayoutObject* ViewportLayoutObject() const;
 
   void CollectAnnotatedRegions(LayoutObject&,
@@ skipping 99 matching lines @@
 #endif
 
   ScrollbarMode horizontal_scrollbar_mode_;
   ScrollbarMode vertical_scrollbar_mode_;
 
   bool horizontal_scrollbar_lock_;
   bool vertical_scrollbar_lock_;
 
   ChildrenSet children_;
   PluginsSet plugins_;
+  ScrollbarsSet scrollbars_;
 
   ScrollOffset pending_scroll_delta_;
   ScrollOffset scroll_offset_;
   IntSize contents_size_;
 
   bool scrollbars_suppressed_;
 
   bool in_update_scrollbars_;
 
   std::unique_ptr<LayoutAnalyzer> analyzer_;
@@ skipping 110 matching lines @@
                   frameViewBase.IsFrameView());
 DEFINE_TYPE_CASTS(FrameView,
                   ScrollableArea,
                   scrollableArea,
                   scrollableArea->IsFrameView(),
                   scrollableArea.IsFrameView());
 
 }  // namespace blink
 
 #endif  // FrameView_h