--- a/gfx/public/nsIRenderingContext.h
+++ b/gfx/public/nsIRenderingContext.h
@@ -749,52 +749,16 @@ public:
     NATIVE_THEBES_CONTEXT = 5
   };
   /**
    * Retrieve the native graphic data given by aType. Return
    * nsnull if not available.
    */
   virtual void* GetNativeGraphicData(GraphicDataType aType) = 0;
 
-  /**
-   * Get a drawing surface used as a backbuffer.
-   * Depending on the platform this will either cause a backbuffer surface to be allocated
-   * or an existing cached backbuffer will be returned. If the backbuffer is being cached
-   * asking for aMaxSize which is different from a previous request may cause the platform
-   * to dump it's cached backbuffer and reallocate a backbuffer of a size which will allow aMaxSize 
-   * buffer to be allocated.
-   *
-   * @param aRequestedSize size of the backbuffer area requested
-   * @param aMaxSize maximum size that may be requested for the backbuffer
-   * @param aForBlending parameter telling if the buffer will be used for blending
-   * @param aBackbuffer drawing surface used as the backbuffer
-   */
-  NS_IMETHOD GetBackbuffer(const nsRect &aRequestedSize, const nsRect &aMaxSize, PRBool aForBlending, nsIDrawingSurface* &aBackbuffer) = 0;
-
-  /**
-   * Release a drawing surface used as the backbuffer
-   * If the platform caches the backbuffer this call will destroy it.
-   */
-  NS_IMETHOD ReleaseBackbuffer(void) = 0;
-
-  /**
-   * Destroy the drawing surface used as the backbuffer. If the platform
-   * does not maintain a cached backbuffer this call will do nothing.
-   */
-  NS_IMETHOD DestroyCachedBackbuffer(void) = 0;
-
-  /**
-   * Some platforms may not want a backbuffer at all. Returning false
-   * here allows them to achieve that
-   *
-   * @param aUseBackbuffer PR_TRUE if we should use a backbuffer, PR_FALSE if not
-   */
-  NS_IMETHOD UseBackbuffer(PRBool* aUseBackbuffer) = 0;
-
-
 #ifdef MOZ_MATHML
   /**
    * Returns bounding metrics (in app units) of an 8-bit character string
    * @param aString string to measure
    * @param aLength number of characters in string
    * @return aBoundingMetrics struct that contains various metrics (see below)
    * @return error status
    */

--- a/gfx/src/beos/nsRenderingContextBeOS.cpp
+++ b/gfx/src/beos/nsRenderingContextBeOS.cpp
@@ -1599,25 +1599,8 @@ nsRenderingContextBeOS::GetBoundingMetri
 		if (utf8str != utf8buf)
 			delete [] utf8str;
 		if (nsnull != aFontID)
 			*aFontID = 0;
 	}		
 	return r;
 }
 #endif /* MOZ_MATHML */
-
-#ifdef NOBBCACHE
-// Do not cache the backbuffer. Doesn't work in BeOS at the moment - cannot repaint
-// Window-attached BVIew. @see bug 95952 for other platforms
-NS_IMETHODIMP nsRenderingContextBeOS::GetBackbuffer(const nsRect &aRequestedSize,
-                                                   const nsRect &aMaxSize,
-                                                   PRBool aForBlending,
-                                                   nsIDrawingSurface* &aBackbuffer)
-{
-  return AllocateBackbuffer(aRequestedSize, aMaxSize, aBackbuffer, PR_FALSE, 0);
-}
- 
-NS_IMETHODIMP nsRenderingContextBeOS::ReleaseBackbuffer(void)
-{
-	return DestroyCachedBackbuffer();
-}
-#endif
\ No newline at end of file

--- a/gfx/src/beos/nsRenderingContextBeOS.h
+++ b/gfx/src/beos/nsRenderingContextBeOS.h
@@ -189,22 +189,16 @@ public:
    * Returns metrics (in app units) of a Unicode character string
    */
   NS_IMETHOD GetBoundingMetrics(const PRUnichar*   aString,
                                 PRUint32           aLength,
                                 nsBoundingMetrics& aBoundingMetrics,
                                 PRInt32*           aFontID = nsnull);
 #endif /* MOZ_MATHML */
 
-#ifdef NOBBCACHE
-	NS_IMETHOD GetBackbuffer(const nsRect &aRequestedSize, const nsRect &aMaxSize,
-                           PRBool aForBlending, nsIDrawingSurface* &aBackbuffer);
-	NS_IMETHOD ReleaseBackbuffer(void);
-#endif
-
   //LockAndUpdateView() - method, similar to UpdateGC (from gtk gfx).
   //Acquires "fresh" drawable mView (BView) from drawing surface, locks it (BeOS specifics),
   //updates font, color and sets clipping region. 
   bool LockAndUpdateView();	
   //Each LockAndUpdateView() statement must have UnlockView() counterpart somewhere, 
   //if returned true.
   void UnlockView();
 

--- a/gfx/src/gtk/nsRenderingContextGTK.cpp
+++ b/gfx/src/gtk/nsRenderingContextGTK.cpp
@@ -1466,24 +1466,8 @@ NS_IMETHODIMP nsRenderingContextGTK::Get
   return mFontMetrics->GetRangeWidth(aText, aLength, aStart, aEnd, aWidth);
 }
 
 NS_IMETHODIMP nsRenderingContextGTK::DrawImage(imgIContainer *aImage, const nsRect & aSrcRect, const nsRect & aDestRect)
 {
   UpdateGC();
   return nsRenderingContextImpl::DrawImage(aImage, aSrcRect, aDestRect);
 }
-
-NS_IMETHODIMP nsRenderingContextGTK::GetBackbuffer(const nsRect &aRequestedSize,
-                                                   const nsRect &aMaxSize,
-                                                   PRBool aForBlending,
-                                                   nsIDrawingSurface* &aBackbuffer)
-{
-  // Do not cache the backbuffer. On GTK it is more efficient to allocate
-  // the backbuffer as needed and it doesn't cause a performance hit. @see bug 95952
-  return AllocateBackbuffer(aRequestedSize, aMaxSize, aBackbuffer, PR_FALSE, 0);
-}
- 
-NS_IMETHODIMP nsRenderingContextGTK::ReleaseBackbuffer(void) {
-  // Do not cache the backbuffer. On GTK it is more efficient to allocate
-  // the backbuffer as needed and it doesn't cause a performance hit. @see bug 95952
-  return DestroyCachedBackbuffer();
-}

--- a/gfx/src/gtk/nsRenderingContextGTK.h
+++ b/gfx/src/gtk/nsRenderingContextGTK.h
@@ -237,20 +237,16 @@ public:
   NS_IMETHOD GetRangeWidth(const char *aText,
                            PRUint32 aLength,
                            PRUint32 aStart,
                            PRUint32 aEnd,
                            PRUint32 &aWidth);
 
   NS_IMETHOD DrawImage(imgIContainer *aImage, const nsRect & aSrcRect, const nsRect & aDestRect);
 
-  NS_IMETHOD GetBackbuffer(const nsRect &aRequestedSize, const nsRect &aMaxSize,
-                           PRBool aForBlending, nsIDrawingSurface* &aBackbuffer);
-  NS_IMETHOD ReleaseBackbuffer(void);
-
   //locals
   NS_IMETHOD CommonInit();
 
   void CreateClipRegion();
 
   GdkGC *GetGC() {
     if (!mGC)
       UpdateGC();

--- a/gfx/src/mac/nsRenderingContextMac.cpp
+++ b/gfx/src/mac/nsRenderingContextMac.cpp
@@ -1511,34 +1511,16 @@ nsRenderingContextMac::DrawTile(imgICont
                     const nsRect * aTargetRect)
 {
   SetupPortState();
   return nsRenderingContextImpl::DrawTile(aImage, aXImageStart, aYImageStart, aTargetRect);
 }
 
 #pragma mark -
 
-// override to set the port back to the window port
-NS_IMETHODIMP
-nsRenderingContextMac::ReleaseBackbuffer(void)
-{
-  SelectOffScreenDrawingSurface(nsnull);
-  return NS_OK;
-}
-
-
-// override to not use a back buffer on MacOS X
-NS_IMETHODIMP 
-nsRenderingContextMac::UseBackbuffer(PRBool* aUseBackbuffer)
-{
-  *aUseBackbuffer = PR_FALSE;
-  return NS_OK;
-}
-
-
 PRBool
 nsRenderingContextMac::OnTigerOrLater()
 {
   static PRBool sInitVer = PR_FALSE;
   static PRBool sOnTigerOrLater = PR_FALSE;
   if (!sInitVer) {
     long version;
     OSErr err = ::Gestalt(gestaltSystemVersion, &version);

--- a/gfx/src/mac/nsRenderingContextMac.h
+++ b/gfx/src/mac/nsRenderingContextMac.h
@@ -177,20 +177,16 @@ public:
 
 #endif /* MOZ_MATHML */
 
   virtual PRInt32 GetMaxStringLength();
                                  
   NS_IMETHOD CopyOffScreenBits(nsIDrawingSurface* aSrcSurf, PRInt32 aSrcX, PRInt32 aSrcY,
                                const nsRect &aDestBounds, PRUint32 aCopyFlags);
 
-  // nsRenderingContextImpl overrides
-  NS_IMETHOD ReleaseBackbuffer(void);
-  NS_IMETHOD UseBackbuffer(PRBool* aUseBackbuffer);
-
   virtual void* GetNativeGraphicData(GraphicDataType aType);
 
   /**
    * Let the device context know whether we want text reordered with
    * right-to-left base direction
    */
   NS_IMETHOD SetRightToLeftText(PRBool aIsRTL);
   NS_IMETHOD GetRightToLeftText(PRBool* aIsRTL);

--- a/gfx/src/nsRenderingContextImpl.h
+++ b/gfx/src/nsRenderingContextImpl.h
@@ -86,21 +86,16 @@ public:
   { return nsnull; }
 
   /**
    * Sets the Pen Mode for the RenderingContext 
    * @param aPenMode The Pen Mode
    * @return NS_OK if the Pen Mode is correctly set
    */
   NS_IMETHOD SetPenMode(nsPenMode aPenMode) { return NS_ERROR_FAILURE;}
-
-  NS_IMETHOD GetBackbuffer(const nsRect &aRequestedSize, const nsRect &aMaxSize, PRBool aForBlending, nsIDrawingSurface* &aBackbuffer); 
-  NS_IMETHOD ReleaseBackbuffer(void);
-  NS_IMETHOD DestroyCachedBackbuffer(void);
-  NS_IMETHOD UseBackbuffer(PRBool* aUseBackbuffer);
   
   NS_IMETHOD PushTranslation(PushedTranslation* aState);
   NS_IMETHOD PopTranslation(PushedTranslation* aState);
   NS_IMETHOD SetTranslation(nscoord aX, nscoord aY);
 
   /**
    * Return the maximum length of a string that can be handled by the platform
    * using the current font metrics.
@@ -312,32 +307,20 @@ protected:
    * Get the size of the offscreen drawing surface..
    *
    * @param aMaxBackbufferSize Maximum size that may be requested for the backbuffer
    * @param aRequestedSize Desired size for the offscreen.
    * @param aSurfaceSize   Offscreen adjusted to a discrete size which encloses aRequestedSize.
    */
   void GetDrawingSurfaceSize(const nsRect& aMaxBackbufferSize, const nsRect& aRequestedSize, nsRect& aSurfaceSize);
 
-  /**
-   * Utility method used to implement NS_IMETHOD GetBackbuffer
-   *
-   * @param aRequestedSize size of the backbuffer area requested
-   * @param aMaxSize maximum size that may be requested for the backbuffer
-   * @param aBackbuffer drawing surface used as the backbuffer
-   * @param aCacheBackbuffer PR_TRUE then the backbuffer will be cached, if PR_FALSE it is created each time
-   * @param aSurfFlags flags passed to CreateDrawingSurface()
-   */
-  nsresult AllocateBackbuffer(const nsRect &aRequestedSize, const nsRect &aMaxSize, nsIDrawingSurface* &aBackbuffer, PRBool aCacheBackbuffer, PRUint32 aSurfFlags);
-
 public:
 
 protected:
   nsPenMode   mPenMode;
 private:
   static nsIDrawingSurface*  gBackbuffer;         //singleton backbuffer 
-  static nsRect            gBackbufferBounds;   //backbuffer bounds
     // Largest requested offscreen size if larger than a full screen.
   static nsSize            gLargestRequestedSize;
 
 };
 
 #endif /* nsRenderingContextImpl */

--- a/gfx/src/shared/nsRenderingContextImpl.cpp
+++ b/gfx/src/shared/nsRenderingContextImpl.cpp
@@ -40,18 +40,16 @@
 #include "nsIDeviceContext.h"
 #include "nsIImage.h"
 #include "nsTransform2D.h"
 #include "nsIRegion.h"
 #include "nsIFontMetrics.h"
 #include <stdlib.h>
 
 
-nsIDrawingSurface* nsRenderingContextImpl::gBackbuffer = nsnull;
-nsRect nsRenderingContextImpl::gBackbufferBounds = nsRect(0, 0, 0, 0);
 nsSize nsRenderingContextImpl::gLargestRequestedSize = nsSize(0, 0);
 
 
 /** ---------------------------------------------------
  *  See documentation in nsIRenderingContext.h
  *	@update 3/16/00 dwc
  */
 nsRenderingContextImpl :: nsRenderingContextImpl()
@@ -67,93 +65,16 @@ nsRenderingContextImpl :: nsRenderingCon
  *	@update 3/16/00 dwc
  */
 nsRenderingContextImpl :: ~nsRenderingContextImpl()
 {
 
 
 }
 
-
-NS_IMETHODIMP nsRenderingContextImpl::GetBackbuffer(const nsRect &aRequestedSize, const nsRect &aMaxSize, PRBool aForBlending, nsIDrawingSurface* &aBackbuffer)
-{
-  // Default implementation assumes the backbuffer will be cached.
-  // If the platform implementation does not require the backbuffer to
-  // be cached override this method and make the following call instead:
-  // AllocateBackbuffer(aRequestedSize, aMaxSize, aBackbuffer, PR_FALSE);
-  return AllocateBackbuffer(aRequestedSize, aMaxSize, aBackbuffer, PR_TRUE, 0);
-}
-
-nsresult nsRenderingContextImpl::AllocateBackbuffer(const nsRect &aRequestedSize, const nsRect &aMaxSize, nsIDrawingSurface* &aBackbuffer, PRBool aCacheBackbuffer, PRUint32 aSurfFlags)
-{
-  nsRect newBounds;
-  nsresult rv = NS_OK;
-
-   if (! aCacheBackbuffer) {
-    newBounds = aRequestedSize;
-  } else {
-    GetDrawingSurfaceSize(aMaxSize, aRequestedSize, newBounds);
-  }
-
-  if ((nsnull == gBackbuffer)
-      || (gBackbufferBounds.width != newBounds.width)
-      || (gBackbufferBounds.height != newBounds.height))
-    {
-      if (gBackbuffer) {
-        //destroy existing DS
-        DestroyDrawingSurface(gBackbuffer);
-        gBackbuffer = nsnull;
-      }
-
-      rv = CreateDrawingSurface(newBounds, aSurfFlags, gBackbuffer);
-      //   printf("Allocating a new drawing surface %d %d\n", newBounds.width, newBounds.height);
-      if (NS_SUCCEEDED(rv)) {
-        gBackbufferBounds = newBounds;
-        SelectOffScreenDrawingSurface(gBackbuffer);
-      } else {
-        gBackbufferBounds.SetRect(0,0,0,0);
-        gBackbuffer = nsnull;
-      }
-    } else {
-      SelectOffScreenDrawingSurface(gBackbuffer);
-
-      nsCOMPtr<nsIDeviceContext>  dx;
-      GetDeviceContext(*getter_AddRefs(dx));
-      nsRect bounds = aRequestedSize;
-      bounds *= dx->AppUnitsPerDevPixel();
-
-      SetClipRect(bounds, nsClipCombine_kReplace);
-    }
-
-  aBackbuffer = gBackbuffer;
-  return rv;
-}
-
-NS_IMETHODIMP nsRenderingContextImpl::ReleaseBackbuffer(void)
-{
-  // If the platform does not require the backbuffer to be cached
-  // override this method and call DestroyCachedBackbuffer
-  return NS_OK;
-}
-
-NS_IMETHODIMP nsRenderingContextImpl::DestroyCachedBackbuffer(void)
-{
-  if (gBackbuffer) {
-    DestroyDrawingSurface(gBackbuffer);
-    gBackbuffer = nsnull;
-  }
-  return NS_OK;
-}
-
-NS_IMETHODIMP nsRenderingContextImpl::UseBackbuffer(PRBool* aUseBackbuffer)
-{
-  *aUseBackbuffer = PR_TRUE;
-  return NS_OK;
-}
-
 NS_IMETHODIMP nsRenderingContextImpl::PushTranslation(PushedTranslation* aState)
 {
   // The transform components are saved and restored instead 
   // of using PushState and PopState because they are too slow
   // because they also save and restore the clip state.
   // Note: Setting a negative translation to restore the 
   // state does not work because the floating point errors can accumulate
   // causing the display of some frames to be off by one pixel. 

--- a/gfx/src/thebes/nsThebesRenderingContext.cpp
+++ b/gfx/src/thebes/nsThebesRenderingContext.cpp
@@ -865,54 +865,16 @@ nsThebesRenderingContext::DrawNativeWidg
     mThebes->Restore();
 
     delete tmpSurf;
 
     return NS_OK;
 }
 
 NS_IMETHODIMP
-nsThebesRenderingContext::UseBackbuffer(PRBool* aUseBackbuffer)
-{
-#ifndef XP_MACOSX
-    *aUseBackbuffer = PR_TRUE;
-#else
-    *aUseBackbuffer = PR_FALSE;
-#endif
-    return NS_OK;
-}
-
-NS_IMETHODIMP
-nsThebesRenderingContext::GetBackbuffer(const nsRect &aRequestedSize,
-                                        const nsRect &aMaxSize,
-                                        PRBool aForBlending,
-                                        nsIDrawingSurface* &aBackbuffer)
-{
-    PR_LOG(gThebesGFXLog, PR_LOG_DEBUG,
-           ("## %p nsTRC::GetBackBuffer req: %d %d %d %d max: %d %d %d %d blending? %d\n",
-            this, aRequestedSize.x, aRequestedSize.y, aRequestedSize.width, aRequestedSize.height,
-            aMaxSize.x, aMaxSize.y, aMaxSize.width, aMaxSize.height, aForBlending));
-
-    return AllocateBackbuffer(aRequestedSize, aMaxSize, aBackbuffer, PR_FALSE,
-                              aForBlending ? NS_CREATEDRAWINGSURFACE_FOR_PIXEL_ACCESS : 0);
-}
-
-NS_IMETHODIMP
-nsThebesRenderingContext::ReleaseBackbuffer(void)
-{
-    return DestroyCachedBackbuffer();
-}
-
-NS_IMETHODIMP
-nsThebesRenderingContext::DestroyCachedBackbuffer(void)
-{
-    return NS_OK;
-}
-
-NS_IMETHODIMP
 nsThebesRenderingContext::PushFilter(const nsRect& twRect, PRBool aAreaIsOpaque, float aOpacity)
 {
     PR_LOG(gThebesGFXLog, PR_LOG_DEBUG,
            ("## %p nsTRC::PushFilter [%d,%d,%d,%d] isOpaque: %d opacity: %f\n",
             this, twRect.x, twRect.y, twRect.width, twRect.height,
             aAreaIsOpaque, aOpacity));
 
     mOpacityArray.AppendElement(aOpacity);

--- a/gfx/src/thebes/nsThebesRenderingContext.h
+++ b/gfx/src/thebes/nsThebesRenderingContext.h
@@ -218,23 +218,16 @@ public:
     NS_IMETHOD PushFilter(const nsRect& aRect, PRBool aAreaIsOpaque, float aOpacity);
     NS_IMETHOD PopFilter();
 
     NS_IMETHOD CopyOffScreenBits(nsIDrawingSurface *aSrcSurf,
                                  PRInt32 aSrcX, PRInt32 aSrcY,
                                  const nsRect &aDestBounds,
                                  PRUint32 aCopyFlags);
     virtual void* GetNativeGraphicData(GraphicDataType aType);
-    NS_IMETHOD GetBackbuffer(const nsRect &aRequestedSize,
-                             const nsRect &aMaxSize,
-                             PRBool aForBlending,
-                             nsIDrawingSurface* &aBackbuffer);
-    NS_IMETHOD ReleaseBackbuffer(void);
-    NS_IMETHOD DestroyCachedBackbuffer(void);
-    NS_IMETHOD UseBackbuffer(PRBool* aUseBackbuffer);
 
     NS_IMETHOD PushTranslation(PushedTranslation* aState);
     NS_IMETHOD PopTranslation(PushedTranslation* aState);
     NS_IMETHOD SetTranslation(nscoord aX, nscoord aY);
 
     NS_IMETHOD DrawImage(imgIContainer *aImage,
                          const nsRect &aSrcRect,
                          const nsRect &aDestRect);

--- a/gfx/src/windows/nsRenderingContextWin.cpp
+++ b/gfx/src/windows/nsRenderingContextWin.cpp
@@ -2856,32 +2856,16 @@ nsRenderingContextWin::ConditionRect(nsR
   aDestRect.left = (aSrcRect.x < kTopLeftLimit)
                       ? kTopLeftLimit
                       : aSrcRect.x;
   aDestRect.right = ((aSrcRect.x + aSrcRect.width) > kBottomRightLimit)
                       ? kBottomRightLimit
                       : (aSrcRect.x + aSrcRect.width);
 }
 
-
-NS_IMETHODIMP 
-nsRenderingContextWin::GetBackbuffer(const nsRect &aRequestedSize, const nsRect &aMaxSize, PRBool aForBlending, nsIDrawingSurface* &aBackbuffer)
-{
-  // Do not cache the backbuffer. On WIN32 it is faster to get allocate
-  // the backbuffer as needed. @see bug 95952
-  return AllocateBackbuffer(aRequestedSize, aMaxSize, aBackbuffer, PR_FALSE, aForBlending ? NS_CREATEDRAWINGSURFACE_FOR_PIXEL_ACCESS : 0);
-}
- 
-NS_IMETHODIMP 
-nsRenderingContextWin::ReleaseBackbuffer(void) {
-  // Destroy the backbuffer. Do not cache it. On WIN32 it is faster to get allocate
-  // the backbuffer as needed. @see bug 95952
-  return DestroyCachedBackbuffer();
-}
-
 /**
  * Let the device context know whether we want text reordered with
  * right-to-left base direction. The Windows implementation does this
  * by calling SetTextAlign() to set or clear the flag TA_RTLREADING
  */
 NS_IMETHODIMP
 nsRenderingContextWin::SetRightToLeftText(PRBool aIsRTL)
 {

--- a/gfx/src/windows/nsRenderingContextWin.h
+++ b/gfx/src/windows/nsRenderingContextWin.h
@@ -223,20 +223,16 @@ public:
 #endif /* MOZ_MATHML */
   virtual PRInt32 GetMaxStringLength();
 
   NS_IMETHOD CopyOffScreenBits(nsIDrawingSurface* aSrcSurf, PRInt32 aSrcX, PRInt32 aSrcY,
                                const nsRect &aDestBounds, PRUint32 aCopyFlags);
   // nsIRenderingContextWin
   NS_IMETHOD CreateDrawingSurface(HDC aDC, nsIDrawingSurface* &aSurface);
 
-  NS_IMETHOD GetBackbuffer(const nsRect &aRequestedSize, const nsRect &aMaxSize, PRBool aForBlending, nsIDrawingSurface* &aBackbuffer);
- 
-  NS_IMETHOD ReleaseBackbuffer(void);
-
   NS_IMETHOD SetRightToLeftText(PRBool aIsRTL);
   NS_IMETHOD GetRightToLeftText(PRBool* aIsRTL);
 
 protected:
   void SetupFontAndColor(void);
 
   ~nsRenderingContextWin();
 

--- a/gfx/src/xlib/nsRenderingContextXlib.cpp
+++ b/gfx/src/xlib/nsRenderingContextXlib.cpp
@@ -2498,30 +2498,8 @@ nsRenderingContextXlib::GetBoundingMetri
 
 NS_IMETHODIMP
 nsRenderingContextXlib::DrawImage(imgIContainer *aImage, const nsRect & aSrcRect, const nsRect & aDestRect)
 {
   PR_LOG(RenderingContextXlibLM, PR_LOG_DEBUG, ("nsRenderingContextXlib::DrawImage()\n"));
   UpdateGC();
   return nsRenderingContextImpl::DrawImage(aImage, aSrcRect, aDestRect);
 }
-
-NS_IMETHODIMP
-nsRenderingContextXlib::GetBackbuffer(const nsRect &aRequestedSize,
-                                      const nsRect &aMaxSize,
-                                      PRBool aForBlending,
-                                      nsIDrawingSurface* &aBackbuffer)
-{
-  PR_LOG(RenderingContextXlibLM, PR_LOG_DEBUG, ("nsRenderingContextXlib::GetBackbuffer()\n"));
-  /* Do not cache the backbuffer. On X11 it is more efficient to allocate
-   * the backbuffer as needed and it doesn't cause a performance hit. @see bug 95952 */
-  return AllocateBackbuffer(aRequestedSize, aMaxSize, aBackbuffer, PR_FALSE, 0);
-}
- 
-NS_IMETHODIMP
-nsRenderingContextXlib::ReleaseBackbuffer(void) 
-{
-  PR_LOG(RenderingContextXlibLM, PR_LOG_DEBUG, ("nsRenderingContextXlib::ReleaseBackbuffer()\n"));
-  /* Do not cache the backbuffer. On X11 it is more efficient to allocate
-   * the backbuffer as needed and it doesn't cause a performance hit. @see bug 95952 */
-  return DestroyCachedBackbuffer();
-}
-

--- a/gfx/src/xlib/nsRenderingContextXlib.h
+++ b/gfx/src/xlib/nsRenderingContextXlib.h
@@ -194,20 +194,16 @@ public:
                                nsTextDimensions& aLastWordDimensions,
                                PRInt32*          aFontID = nsnull);
 
   NS_IMETHOD CopyOffScreenBits(nsIDrawingSurface* aSrcSurf, PRInt32 aSrcX, PRInt32 aSrcY,
                                const nsRect &aDestBounds, PRUint32 aCopyFlags);
 
   NS_IMETHOD DrawImage(imgIContainer *aImage, const nsRect & aSrcRect, const nsRect & aDestRect);
 
-  NS_IMETHOD GetBackbuffer(const nsRect &aRequestedSize, const nsRect &aMaxSize,
-                           PRBool aForBlending, nsIDrawingSurface* &aBackbuffer);
-  NS_IMETHOD ReleaseBackbuffer(void);
-
 #ifdef MOZ_MATHML
   /**
    * Returns metrics (in app units) of an 8-bit character string
    */
   NS_IMETHOD GetBoundingMetrics(const char*        aString,
                                 PRUint32           aLength,
                                 nsBoundingMetrics& aBoundingMetrics);
   

--- a/layout/generic/nsObjectFrame.cpp
+++ b/layout/generic/nsObjectFrame.cpp
@@ -536,25 +536,16 @@ nsObjectFrame::CreateWidget(nscoord aWid
     return NS_OK;       //XXX why OK? MMP
   }
 
   nsIViewManager* viewMan = view->GetViewManager();
   // mark the view as hidden since we don't know the (x,y) until Paint
   // XXX is the above comment correct?
   viewMan->SetViewVisibility(view, nsViewVisibility_kHide);
 
-  // Turn off double buffering on the Mac. This depends on bug 49743 and partially
-  // fixes 32327, 19931 and 51787
-#ifdef XP_MACOSX
-  PRBool doubleBuffer =
-    nsContentUtils::GetBoolPref("plugin.enable_double_buffer");
-  
-  viewMan->AllowDoubleBuffering(doubleBuffer);
-#endif
-  
   //this is ugly. it was ripped off from didreflow(). MMP
   // Position and size view relative to its parent, not relative to our
   // parent frame (our parent frame may not have a view).
   
   nsIView* parentWithView;
   nsPoint origin;
   nsRect r(0, 0, mRect.width, mRect.height);
 

--- a/view/public/nsIViewManager.h
+++ b/view/public/nsIViewManager.h
@@ -435,27 +435,16 @@ public:
    * Force update of view manager widget
    * Callers should use UpdateView(view, NS_VMREFRESH_IMMEDIATE) in most cases instead
    * @result error status
    */
   // XXXbz Callers seem to be confused about this one... and it doesn't play
   // right with view update batching at all (will miss updates).  Maybe this
   // should call FlushPendingInvalidates()?
   NS_IMETHOD ForceUpdate() = 0;
-  
-  /**
-   * Control double buffering of the display. If double buffering
-   * is enabled the viewmanager is allowed to render to an offscreen
-   * drawing surface before copying to the display in order to prevent
-   * flicker. If it is disabled all rendering will appear directly on the
-   * the display. The display is double buffered by default.
-   * @param aDoubleBuffer PR_TRUE to enable double buffering
-   *                      PR_FALSE to disable double buffering
-   */
-  NS_IMETHOD AllowDoubleBuffering(PRBool aDoubleBuffer)=0;
 
   /**
    * Indicate whether the viewmanager is currently painting
    *
    * @param aPainting PR_TRUE if the viewmanager is painting
    *                  PR_FALSE otherwise
    */
   NS_IMETHOD IsPainting(PRBool& aIsPainting)=0;

--- a/view/src/nsViewManager.cpp
+++ b/view/src/nsViewManager.cpp
@@ -59,19 +59,17 @@
 #include "nsIPrefService.h"
 #include "nsRegion.h"
 #include "nsInt64.h"
 #include "nsScrollPortView.h"
 #include "nsHashtable.h"
 #include "nsCOMArray.h"
 #include "nsThreadUtils.h"
 
-#ifdef MOZ_CAIRO_GFX
 #include "gfxContext.h"
-#endif
 
 static NS_DEFINE_IID(kBlenderCID, NS_BLENDER_CID);
 static NS_DEFINE_IID(kRegionCID, NS_REGION_CID);
 static NS_DEFINE_IID(kRenderingContextCID, NS_RENDERING_CONTEXT_CID);
 
 /**
    XXX TODO XXX
 
@@ -171,17 +169,16 @@ nsViewManager::nsViewManager()
   }
 
   gViewManagers->AppendElement(this);
 
   mVMCount++;
   // NOTE:  we use a zeroing operator new, so all data members are
   // assumed to be cleared here.
   mDefaultBackgroundColor = NS_RGBA(0, 0, 0, 0);
-  mAllowDoubleBuffering = PR_TRUE; 
   mHasPendingUpdates = PR_FALSE;
   mRecursiveRefreshPending = PR_FALSE;
   mUpdateBatchFlags = 0;
 }
 
 nsViewManager::~nsViewManager()
 {
   if (mRootView) {
@@ -220,24 +217,16 @@ nsViewManager::~nsViewManager()
     gViewManagers = nsnull;
 
     // Cleanup all of the offscreen drawing surfaces if the last view manager
     // has been destroyed and there is something to cleanup
 
     // Note: A global rendering context is needed because it is not possible 
     // to create a nsIRenderingContext during the shutdown of XPCOM. The last
     // viewmanager is typically destroyed during XPCOM shutdown.
-
-    if (gCleanupContext) {
-
-      gCleanupContext->DestroyCachedBackbuffer();
-    } else {
-      NS_ASSERTION(PR_FALSE, "Cleanup of drawing surfaces + offscreen buffer failed");
-    }
-
     NS_IF_RELEASE(gCleanupContext);
   }
 
   mObserver = nsnull;
   mContext = nsnull;
 
   if (nsnull != mCompositeListeners) {
     mCompositeListeners->Clear();
@@ -497,35 +486,16 @@ void nsViewManager::Refresh(nsView *aVie
 
   NS_ASSERTION(!IsPainting(), "recursive painting not permitted");
   if (IsPainting()) {
     RootViewManager()->mRecursiveRefreshPending = PR_TRUE;
     return;
   }  
   SetPainting(PR_TRUE);
 
-  // force double buffering in general
-  aUpdateFlags |= NS_VMREFRESH_DOUBLE_BUFFER;
-
-  if (!DoDoubleBuffering())
-    aUpdateFlags &= ~NS_VMREFRESH_DOUBLE_BUFFER;
-
-  // check if the rendering context wants double-buffering or not
-  if (aContext) {
-    PRBool contextWantsBackBuffer = PR_TRUE;
-    aContext->UseBackbuffer(&contextWantsBackBuffer);
-    if (!contextWantsBackBuffer)
-      aUpdateFlags &= ~NS_VMREFRESH_DOUBLE_BUFFER;
-  }
-  
-  if (PR_FALSE == mAllowDoubleBuffering) {
-    // Turn off double-buffering of the display
-    aUpdateFlags &= ~NS_VMREFRESH_DOUBLE_BUFFER;
-  }
-
   nsCOMPtr<nsIRenderingContext> localcx;
   nsIDrawingSurface*    ds = nsnull;
 
   if (nsnull == aContext)
     {
       localcx = CreateRenderingContext(*aView);
 
       //couldn't get rendering context. this is ok at init time atleast
@@ -550,121 +520,31 @@ void nsViewManager::Refresh(nsView *aVie
       }
     }
   }
 
   // damageRect is the clipped damage area bounds, in twips-relative-to-view-origin
   nsRect damageRect = damageRegion.GetBounds();
   PRInt32 p2a = mContext->AppUnitsPerDevPixel();
 
-#ifdef MOZ_CAIRO_GFX
   nsRefPtr<gfxContext> ctx =
     (gfxContext*) localcx->GetNativeGraphicData(nsIRenderingContext::NATIVE_THEBES_CONTEXT);
 
   ctx->Save();
 
   ctx->Translate(gfxPoint(NSAppUnitsToIntPixels(viewRect.x, p2a),
                           NSAppUnitsToIntPixels(viewRect.y, p2a)));
 
   nsRegion opaqueRegion;
   AddCoveringWidgetsToOpaqueRegion(opaqueRegion, mContext, aView);
   damageRegion.Sub(damageRegion, opaqueRegion);
 
   RenderViews(aView, *localcx, damageRegion, ds);
 
   ctx->Restore();
-#else
-  // widgetDamageRectInPixels is the clipped damage area bounds,
-  // in pixels-relative-to-widget-origin
-  nsRect widgetDamageRectInPixels = damageRect;
-  widgetDamageRectInPixels.MoveBy(-viewRect.x, -viewRect.y);
-  widgetDamageRectInPixels.ScaleRoundOut(t2p);
-
-  // On the Mac, we normally turn doublebuffering off because Quartz is
-  // doublebuffering for us. But we need to turn it on anyway if we need
-  // to use our blender, which requires access to the "current pixel values"
-  // when it blends onto the canvas.
-  // XXX disable opacity for now on the Mac because of this ... it'll get
-  // reenabled with cairo
-  if (aUpdateFlags & NS_VMREFRESH_DOUBLE_BUFFER)
-  {
-    nsRect maxWidgetSize;
-    GetMaxWidgetBounds(maxWidgetSize);
-
-    nsRect r(0, 0, widgetDamageRectInPixels.width, widgetDamageRectInPixels.height);
-    if (NS_FAILED(localcx->GetBackbuffer(r, maxWidgetSize, PR_FALSE, ds))) {
-      //Failed to get backbuffer so turn off double buffering
-      aUpdateFlags &= ~NS_VMREFRESH_DOUBLE_BUFFER;
-    }
-  }
-
-  nsIRenderingContext::PushedTranslation trans;
-  nsPoint delta(0,0);
-
-  // painting will be done in aView's coordinates
-  PRBool usingDoubleBuffer = (aUpdateFlags & NS_VMREFRESH_DOUBLE_BUFFER) && ds;
-  if (usingDoubleBuffer) {
-    // Adjust translations because the backbuffer holds just the damaged area,
-    // not the whole widget
-
-    localcx->PushTranslation(&trans);
-
-    // We want (0,0) to be translated to the widget origin. We do it this
-    // way rather than calling Translate because it is *imperative* that
-    // the tx,ty floats in the translation matrix get set to an integer
-    // number of pixels. For example, if they're off by 0.000001 for some
-    // damage rects, then a translated coordinate of NNNN.5 may get rounded
-    // differently depending on what damage rect is used to paint the object,
-    // and we may get inconsistent rendering depending on what area was
-    // damaged.
-    localcx->SetTranslation(-widgetDamageRectInPixels.x, -widgetDamageRectInPixels.y);
-    
-    // We're going to reset the clip region for the backbuffer. We can't
-    // just use damageRegion because nsIRenderingContext::SetClipRegion doesn't
-    // translate/scale the coordinates (grrrrrrrrrr)
-    // So we have to translate the region before we use it. aRegion is in
-    // pixels-relative-to-widget-origin, so:
-    aRegion->Offset(-widgetDamageRectInPixels.x, -widgetDamageRectInPixels.y);
-  }
-  // RenderViews draws in view coordinates. We want (0,0)
-  // to be translated to (viewRect.x,viewRect.y) in the widget. So:
-  localcx->Translate(viewRect.x, viewRect.y);
-
-  // Note that nsIRenderingContext::SetClipRegion always works in pixel coordinates,
-  // and nsIRenderingContext::SetClipRect always works in app coordinates. Stupid huh?
-  // Also, SetClipRegion doesn't subject its argument to the current transform, but
-  // SetClipRect does.
-  localcx->SetClipRegion(*aRegion, nsClipCombine_kReplace);
-  localcx->SetClipRect(damageRect, nsClipCombine_kIntersect);
-
-  nsRegion opaqueRegion;
-  AddCoveringWidgetsToOpaqueRegion(opaqueRegion, mContext, aView);
-  damageRegion.Sub(damageRegion, opaqueRegion);
-
-  RenderViews(aView, *localcx, damageRegion, ds);
-
-  // undo earlier translation
-  localcx->Translate(-viewRect.x, -viewRect.y);
-  if (usingDoubleBuffer) {
-    // Flush bits back to the screen
-
-    // Restore aRegion to pixels-relative-to-widget-origin
-    aRegion->Offset(widgetDamageRectInPixels.x, widgetDamageRectInPixels.y);
-    // Restore translation to its previous state
-    localcx->PopTranslation(&trans);
-    // Make damageRect twips-relative-to-widget-origin
-    damageRect.MoveBy(-viewRect.x, -viewRect.y);
-    // Reset clip region to widget-relative
-    localcx->SetClipRegion(*aRegion, nsClipCombine_kReplace);
-    localcx->SetClipRect(damageRect, nsClipCombine_kIntersect);
-    // neither source nor destination are transformed
-    localcx->CopyOffScreenBits(ds, 0, 0, widgetDamageRectInPixels, NS_COPYBITS_USE_SOURCE_CLIP_REGION);
-    localcx->ReleaseBackbuffer();
-  }
-#endif
 
   SetPainting(PR_FALSE);
 
   // notify the listeners.
   if (nsnull != mCompositeListeners) {
     PRUint32 listenerCount;
     if (NS_SUCCEEDED(mCompositeListeners->Count(&listenerCount))) {
       nsCOMPtr<nsICompositeListener> listener;
@@ -773,68 +653,27 @@ void nsViewManager::AddCoveringWidgetsTo
 /*
   aRCSurface is the drawing surface being used to double-buffer aRC, or null
   if no double-buffering is happening. We pass this in here so that we can
   blend directly into the double-buffer offscreen memory.
 */
 void nsViewManager::RenderViews(nsView *aView, nsIRenderingContext& aRC,
                                 const nsRegion& aRegion, nsIDrawingSurface* aRCSurface)
 {
-#ifndef MOZ_CAIRO_GFX
-  BlendingBuffers* buffers = nsnull;
-  nsIWidget* widget = aView->GetWidget();
-  PRBool translucentWindow = PR_FALSE;
-  if (widget) {
-    widget->GetWindowTranslucency(translucentWindow);
-    if (translucentWindow) {
-      NS_WARNING("Transparent window enabled");
-      NS_ASSERTION(aRCSurface, "Cannot support transparent windows with doublebuffering disabled");
-
-      // Create a buffer wrapping aRC (which is usually the double-buffering offscreen buffer).
-      buffers = CreateBlendingBuffers(&aRC, PR_TRUE, aRCSurface, translucentWindow, aRegion.GetBounds());
-      NS_ASSERTION(buffers, "Failed to create rendering buffers");
-      if (!buffers)
-        return;
-    }
-  }
-#endif
-
   if (mObserver) {
     nsView* displayRoot = GetDisplayRootFor(aView);
     nsPoint offsetToRoot = aView->GetOffsetTo(displayRoot); 
     nsRegion damageRegion(aRegion);
     damageRegion.MoveBy(offsetToRoot);
     
     aRC.PushState();
     aRC.Translate(-offsetToRoot.x, -offsetToRoot.y);
     mObserver->Paint(displayRoot, &aRC, damageRegion);
     aRC.PopState();
-#ifndef MOZ_CAIRO_GFX
-    if (translucentWindow)
-      mObserver->Paint(displayRoot, buffers->mWhiteCX, aRegion);
-#endif
   }
-
-#ifndef MOZ_CAIRO_GFX
-  if (translucentWindow) {
-    // Get the alpha channel into an array so we can send it to the widget
-    nsRect r = aRegion.GetBounds();
-    r *= (1.0f / mContext->AppUnitsPerDevPixel());
-    nsRect bufferRect(0, 0, r.width, r.height);
-    PRUint8* alphas = nsnull;
-    nsresult rv = mBlender->GetAlphas(bufferRect, buffers->mBlack,
-                                      buffers->mWhite, &alphas);
-    
-    if (NS_SUCCEEDED(rv)) {
-      widget->UpdateTranslucentWindowAlpha(r, alphas);
-    }
-    delete[] alphas;
-    delete buffers;
-  }
-#endif
 }
 
 static nsresult NewOffscreenContext(nsIDeviceContext* deviceContext, nsIDrawingSurface* surface,
                                     const nsRect& aRect, nsIRenderingContext* *aResult)
 {
   nsresult             rv;
   nsIRenderingContext *context = nsnull;
 
@@ -1333,22 +1172,20 @@ NS_IMETHODIMP nsViewManager::DispatchEve
               vm->DoSetWindowDimensions(vm->mDelayedResize.width,
                                         vm->mDelayedResize.height);
               vm->mDelayedResize.SizeTo(NSCOORD_NONE, NSCOORD_NONE);
 
               // Paint later.
               vm->UpdateView(vm->mRootView, NS_VMREFRESH_NO_SYNC);
               didResize = PR_TRUE;
 
-#ifdef MOZ_CAIRO_GFX
               // not sure if it's valid for us to claim that we
               // ignored this, but we're going to do so anyway, since
               // we didn't actually paint anything
               *aStatus = nsEventStatus_eIgnore;
-#endif
             }
           }
 
           if (!didResize) {
             //NS_ASSERTION(IsViewVisible(view), "painting an invisible view");
 
             // Just notify our own view observer that we're about to paint
             // XXXbz do we need to notify other view observers for viewmanagers
@@ -1439,19 +1276,16 @@ NS_IMETHODIMP nsViewManager::DispatchEve
 
 
     case NS_DISPLAYCHANGED:
 
       //Destroy the cached backbuffer to force a new backbuffer
       //be constructed with the appropriate display depth.
       //@see bugzilla bug 6061
       *aStatus = nsEventStatus_eConsumeDoDefault;
-      if (gCleanupContext) {
-        gCleanupContext->DestroyCachedBackbuffer();
-      }
       break;
 
     case NS_SYSCOLORCHANGED:
       {
         // Hold a refcount to the observer. The continued existence of the observer will
         // delay deletion of this view hierarchy should the event want to cause its
         // destruction in, say, some JavaScript event handler.
         nsView *view = nsView::GetViewFor(aEvent->widget);
@@ -2537,24 +2371,16 @@ NS_IMETHODIMP nsViewManager::GetRectVisi
            absRect.x > visibleRect.x + visibleRect.width - aMinTwips)
     *aRectVisibility = nsRectVisibility_kRightOfViewport;
   else
     *aRectVisibility = nsRectVisibility_kVisible;
 
   return NS_OK;
 }
 
-
-NS_IMETHODIMP
-nsViewManager::AllowDoubleBuffering(PRBool aDoubleBuffer)
-{
-  mAllowDoubleBuffering = aDoubleBuffer;
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 nsViewManager::IsPainting(PRBool& aIsPainting)
 {
   aIsPainting = IsPainting();
   return NS_OK;
 }
 
 void

--- a/view/src/nsViewManager.h
+++ b/view/src/nsViewManager.h
@@ -229,17 +229,16 @@ public:
 
   NS_IMETHOD AddCompositeListener(nsICompositeListener *aListener);
   NS_IMETHOD RemoveCompositeListener(nsICompositeListener *aListener);
 
   NS_IMETHOD GetWidget(nsIWidget **aWidget);
   nsIWidget* GetWidget() { return mRootView ? mRootView->GetWidget() : nsnull; }
   NS_IMETHOD ForceUpdate();
  
-  NS_IMETHOD AllowDoubleBuffering(PRBool aDoubleBuffer);
   NS_IMETHOD IsPainting(PRBool& aIsPainting);
   NS_IMETHOD SetDefaultBackgroundColor(nscolor aColor);
   NS_IMETHOD GetDefaultBackgroundColor(nscolor* aColor);
   NS_IMETHOD GetLastUserEventTime(PRUint32& aTime);
   void ProcessInvalidateEvent();
   static PRInt32 GetViewManagerCount();
   static const nsVoidArray* GetViewManagerArray();
   static PRUint32 gLastUserEventTime;
@@ -481,17 +480,16 @@ private:
 
   nsCOMPtr<nsIBlender> mBlender;
   nsISupportsArray  *mCompositeListeners;
   nsCOMPtr<nsIFactory> mRegionFactory;
   nsView            *mRootView;
   // mRootViewManager is a strong ref unless it equals |this|.  It's
   // never null (if we have no ancestors, it will be |this|).
   nsViewManager     *mRootViewManager;
-  PRPackedBool      mAllowDoubleBuffering;
 
   nsRevocableEventPtr<nsViewManagerEvent> mSynthMouseMoveEvent;
   nsRevocableEventPtr<nsViewManagerEvent> mInvalidateEvent;
 
   // The following members should not be accessed directly except by
   // the root view manager.  Some have accessor functions to enforce
   // this, as noted.