--- a/layout/base/nsDisplayList.cpp
+++ b/layout/base/nsDisplayList.cpp
@@ -1525,16 +1525,18 @@ nsDisplayBackgroundImage::nsDisplayBackg
     }
 
     // Check if this background layer is attachment-fixed
     if (!mBackgroundStyle->mLayers[mLayer].mImage.IsEmpty() &&
         mBackgroundStyle->mLayers[mLayer].mAttachment == NS_STYLE_BG_ATTACHMENT_FIXED) {
       aBuilder->SetHasFixedItems();
     }
   }
+
+  mBounds = GetBoundsInternal();
 }
 
 nsDisplayBackgroundImage::~nsDisplayBackgroundImage()
 {
 #ifdef NS_BUILD_REFCNT_LOGGING
   MOZ_COUNT_DTOR(nsDisplayBackgroundImage);
 #endif
 }
@@ -2092,16 +2094,21 @@ void nsDisplayBackgroundImage::ComputeIn
     // painting area.
     aInvalidRegion->Xor(bounds, geometry->mBounds);
   }
 }
 
 nsRect
 nsDisplayBackgroundImage::GetBounds(nsDisplayListBuilder* aBuilder, bool* aSnap) {
   *aSnap = true;
+  return mBounds;
+}
+
+nsRect
+nsDisplayBackgroundImage::GetBoundsInternal() {
   nsPresContext* presContext = mFrame->PresContext();
 
   if (mIsThemed) {
     nsRect r(nsPoint(0,0), mFrame->GetSize());
     presContext->GetTheme()->
         GetWidgetOverflow(presContext->DeviceContext(), mFrame,
                           mFrame->GetStyleDisplay()->mAppearance, &r);
 #ifdef XP_MACOSX

--- a/layout/base/nsDisplayList.h
+++ b/layout/base/nsDisplayList.h
@@ -1894,23 +1894,26 @@ public:
 protected:
   typedef class mozilla::layers::ImageContainer ImageContainer;
   typedef class mozilla::layers::ImageLayer ImageLayer;
 
   bool TryOptimizeToImageLayer(nsDisplayListBuilder* aBuilder);
   bool IsSingleFixedPositionImage(nsDisplayListBuilder* aBuilder,
                                   const nsRect& aClipRect,
                                   gfxRect* aDestRect);
+  nsRect GetBoundsInternal();
 
   // Cache the result of nsCSSRendering::FindBackground. Always null if
   // mIsThemed is true or if FindBackground returned false.
   const nsStyleBackground* mBackgroundStyle;
   /* If this background can be a simple image layer, we store the format here. */
   nsRefPtr<ImageContainer> mImageContainer;
   gfxRect mDestRect;
+  /* Bounds of this display item */
+  nsRect mBounds;
   uint32_t mLayer;
 
   nsITheme::Transparency mThemeTransparency;
   /* Used to cache mFrame->IsThemed() since it isn't a cheap call */
   bool mIsThemed;
   /* true if this item represents the bottom-most background layer */
   bool mIsBottommostLayer;
 };