--- a/gfx/thebes/gfxContext.cpp
+++ b/gfx/thebes/gfxContext.cpp
@@ -590,27 +590,29 @@ gfxContext::PopClip()
 {
   MOZ_ASSERT(CurrentState().pushedClips.Length() > 0);
 
   CurrentState().pushedClips.RemoveElementAt(CurrentState().pushedClips.Length() - 1);
   mDT->PopClip();
 }
 
 gfxRect
-gfxContext::GetClipExtents() const
+gfxContext::GetClipExtents(ClipExtentsSpace aSpace) const
 {
   Rect rect = GetAzureDeviceSpaceClipBounds();
 
   if (rect.width == 0 || rect.height == 0) {
     return gfxRect(0, 0, 0, 0);
   }
 
-  Matrix mat = mTransform;
-  mat.Invert();
-  rect = mat.TransformBounds(rect);
+  if (aSpace == eUserSpace) {
+    Matrix mat = mTransform;
+    mat.Invert();
+    rect = mat.TransformBounds(rect);
+  }
 
   return ThebesRect(rect);
 }
 
 bool
 gfxContext::ExportClip(ClipExporter& aExporter)
 {
   for (unsigned int i = 0; i < mStateStack.Length(); i++) {

--- a/gfx/thebes/gfxContext.h
+++ b/gfx/thebes/gfxContext.h
@@ -372,21 +372,26 @@ public:
      * Any current path will be destroyed by these functions!
      */
     void Clip(const Rect& rect);
     void Clip(const gfxRect& rect); // will clip to a rect
     void Clip(Path* aPath);
 
     void PopClip();
 
+    enum ClipExtentsSpace {
+        eUserSpace = 0,
+        eDeviceSpace = 1,
+    };
+
     /**
-     * This will return the current bounds of the clip region in user
-     * space.
+     * According to aSpace, this function will return the current bounds of
+     * the clip region in user space or device space.
      */
-    gfxRect GetClipExtents() const;
+    gfxRect GetClipExtents(ClipExtentsSpace aSpace = eUserSpace) const;
 
     /**
      * Returns true if the given rectangle is fully contained in the current clip.
      * This is conservative; it may return false even when the given rectangle is
      * fully contained by the current clip.
      */
     bool ClipContainsRect(const gfxRect& aRect);