Layout overflow from transforms should update frame scrollbars

Source/platform/scroll/ScrollView.h

 /*
  * Copyright (C) 2004, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Holger Hans Peter Freyther
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 17 matching lines @@
 #define ScrollView_h
 
 #include "platform/PlatformExport.h"
 #include "platform/Widget.h"
 #include "platform/geometry/IntRect.h"
 #include "platform/scroll/ScrollTypes.h"
 #include "platform/scroll/ScrollableArea.h"
 #include "platform/scroll/Scrollbar.h"
 
 #include "wtf/HashSet.h"
+#include "wtf/TemporaryChange.h"
 
 namespace WebCore {
 
 class HostWindow;
 class Scrollbar;
 
 class PLATFORM_EXPORT ScrollView : public Widget, public ScrollableArea {
 public:
     virtual ~ScrollView();
 
@@ skipping 239 matching lines @@
         Incremental
     };
     void computeScrollbarExistence(bool& newHasHorizontalScrollbar, bool& newHasVerticalScrollbar, ComputeScrollbarExistenceOption = FirstPass) const;
     void updateScrollbarGeometry();
 
     // Called to update the scrollbars to accurately reflect the state of the view.
     void updateScrollbars(const IntSize& desiredOffset);
 
     IntSize excludeScrollbars(const IntSize&) const;
 
+    class InUpdateScrollbarsScope {
+    public:
+        explicit InUpdateScrollbarsScope(ScrollView* view)
+            : m_scope(view->m_inUpdateScrollbars, true)
+        { }
+    private:
+        TemporaryChange<bool> m_scope;
+    };
+
 private:
     bool adjustScrollbarExistence(ComputeScrollbarExistenceOption = FirstPass);
 
     RefPtr<Scrollbar> m_horizontalScrollbar;
     RefPtr<Scrollbar> m_verticalScrollbar;
     ScrollbarMode m_horizontalScrollbarMode;
     ScrollbarMode m_verticalScrollbarMode;
 
     bool m_horizontalScrollbarLock;
     bool m_verticalScrollbarLock;
@@ skipping 23 matching lines @@
 
     void calculateOverhangAreasForPainting(IntRect& horizontalOverhangRect, IntRect& verticalOverhangRect);
     void updateOverhangAreas();
 }; // class ScrollView
 
 DEFINE_TYPE_CASTS(ScrollView, Widget, widget, widget->isScrollView(), widget.isScrollView());
 
 } // namespace WebCore
 
 #endif // ScrollView_h