Trigger style recalc when the window's active state change

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
    modify it under the terms of the GNU Library General Public
@@ skipping 116 matching lines @@
     void updateAcceleratedCompositingSettings();
 
     void recalcOverflowAfterStyleChange();
 
     bool isEnclosedInCompositingLayer() const;
 
     void resetScrollbars();
     void prepareForDetach();
     void detachCustomScrollbars();
     void recalculateCustomScrollbarStyle();
+    void invalidateAllCustomScrollbarsOnActiveChanged();
     virtual void recalculateScrollbarOverlayStyle();
 
     void clear();
 
     bool isTransparent() const;
     void setTransparent(bool isTransparent);
 
     // True if the FrameView is not transparent, and the base background color is opaque.
     bool hasOpaqueBackground() const;
 
@@ skipping 696 matching lines @@
     }
 
 private:
     RawPtrWillBeMember<FrameView> m_view;
     bool m_originalValue;
 };
 
 } // namespace blink
 
 #endif // FrameView_h