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//
// nsNativeScrollbarFrame
//
// A class that wraps a nsIWidget that is a native scrollbar
// and keeps the two in sync with the rest of gecko. Allows us to
// shim a native scrollbar into the GFX scroll-view mechanism.
// 

#ifndef nsNativeScrollbarFrame_h__
#define nsNativeScrollbarFrame_h__


#include "nsScrollbarFrame.h"
#include "nsIWidget.h"

class nsISupportsArray;
class nsIPresShell;
class nsIPresContext;
class nsIContent;
class nsStyleContext;

nsresult NS_NewNativeScrollbarFrame(nsIPresShell* aPresShell, nsIFrame** aResult) ;


class nsNativeScrollbarFrame : public nsBoxFrame
{
public:
  nsNativeScrollbarFrame(nsIPresShell* aShell);
  virtual ~nsNativeScrollbarFrame ( ) ;

#ifdef DEBUG
  NS_IMETHOD GetFrameName(nsAString& aResult) const {
    return MakeFrameName(NS_LITERAL_STRING("NativeScrollbarFrame"), aResult);
  }
#endif

  NS_IMETHOD Init(nsIPresContext* aPresContext, nsIContent* aContent,
                    nsIFrame* aParent, nsStyleContext* aContext, nsIFrame* aPrevInFlow);
           
  // nsIFrame overrides
  NS_IMETHOD AttributeChanged(nsIPresContext* aPresContext, nsIContent* aChild,
                              PRInt32 aNameSpaceID, nsIAtom* aAttribute,
                              PRInt32 aModType);

  NS_IMETHOD QueryInterface(const nsIID& aIID, void** aInstancePtr);
  NS_IMETHOD_(nsrefcnt) AddRef() { return NS_OK; }
  NS_IMETHOD_(nsrefcnt) Release() { return NS_OK; }

  NS_IMETHOD Reflow(nsIPresContext*          aPresContext,
                    nsHTMLReflowMetrics&     aDesiredSize,
                    const nsHTMLReflowState& aReflowState,
                    nsReflowStatus&          aStatus);

  NS_IMETHOD GetPrefSize(nsBoxLayoutState& aState, nsSize& aSize);
                        
protected:
  
  void Hookup();

  nsresult FindScrollbar(nsIFrame* start, nsIFrame** outFrame, nsIContent** outContent);
  
  PRBool IsVertical() const { return mIsVertical; }
                  
private:

  PRPackedBool mIsVertical;
  PRPackedBool mScrollbarNeedsContent;
  nsCOMPtr<nsIWidget> mScrollbar;
  
}; // class nsNativeScrollbarFrame

#endif
