--- a/layout/generic/TextOverflow.cpp
+++ b/layout/generic/TextOverflow.cpp
@@ -100,21 +100,18 @@ static bool
 IsFullyClipped(nsTextFrame* aFrame, nscoord aLeft, nscoord aRight,
                nscoord* aSnappedLeft, nscoord* aSnappedRight)
 {
   *aSnappedLeft = aLeft;
   *aSnappedRight = aRight;
   if (aLeft <= 0 && aRight <= 0) {
     return false;
   }
-  nsRefPtr<nsRenderingContext> rc =
-    aFrame->PresContext()->PresShell()->GetReferenceRenderingContext();
-  return rc &&
-    !aFrame->MeasureCharClippedText(rc->ThebesContext(), aLeft, aRight,
-                                    aSnappedLeft, aSnappedRight);
+  return !aFrame->MeasureCharClippedText(aLeft, aRight,
+                                         aSnappedLeft, aSnappedRight);
 }
 
 static bool
 IsHorizontalOverflowVisible(nsIFrame* aFrame)
 {
   NS_PRECONDITION(nsLayoutUtils::GetAsBlock(aFrame) != nsnull,
                   "expected a block frame");
 

--- a/layout/generic/nsTextFrame.h
+++ b/layout/generic/nsTextFrame.h
@@ -284,28 +284,26 @@ public:
   /**
    * Calculate the horizontal bounds of the grapheme clusters that fit entirely
    * inside the given left/right edges (which are positive lengths from the
    * respective frame edge).  If an input value is zero it is ignored and the
    * result for that edge is zero.  All out parameter values are undefined when
    * the method returns false.
    * @return true if at least one whole grapheme cluster fit between the edges
    */
-  bool MeasureCharClippedText(gfxContext* aCtx,
-                              nscoord aLeftEdge, nscoord aRightEdge,
+  bool MeasureCharClippedText(nscoord aLeftEdge, nscoord aRightEdge,
                               nscoord* aSnappedLeftEdge,
                               nscoord* aSnappedRightEdge);
   /**
    * Same as above; this method also the returns the corresponding text run
    * offset and number of characters that fit.  All out parameter values are
    * undefined when the method returns false.
    * @return true if at least one whole grapheme cluster fit between the edges
    */
-  bool MeasureCharClippedText(gfxContext* aCtx,
-                              PropertyProvider& aProvider,
+  bool MeasureCharClippedText(PropertyProvider& aProvider,
                               nscoord aLeftEdge, nscoord aRightEdge,
                               PRUint32* aStartOffset, PRUint32* aMaxLength,
                               nscoord* aSnappedLeftEdge,
                               nscoord* aSnappedRightEdge);
   // primary frame paint method called from nsDisplayText
   // The private DrawText() is what applies the text to a graphics context
   void PaintText(nsRenderingContext* aRenderingContext, nsPoint aPt,
                  const nsRect& aDirtyRect, const nsCharClipDisplayItem& aItem);

--- a/layout/generic/nsTextFrameThebes.cpp
+++ b/layout/generic/nsTextFrameThebes.cpp
@@ -5267,35 +5267,34 @@ ComputeTransformedLength(PropertyProvide
 {
   gfxSkipCharsIterator iter(aProvider.GetStart());
   PRUint32 start = iter.GetSkippedOffset();
   iter.AdvanceOriginal(aProvider.GetOriginalLength());
   return iter.GetSkippedOffset() - start;
 }
 
 bool
-nsTextFrame::MeasureCharClippedText(gfxContext* aCtx,
-                                    nscoord aLeftEdge, nscoord aRightEdge,
+nsTextFrame::MeasureCharClippedText(nscoord aLeftEdge, nscoord aRightEdge,
                                     nscoord* aSnappedLeftEdge,
                                     nscoord* aSnappedRightEdge)
 {
-  // Don't pass in aRenderingContext here, because we need a *reference*
-  // context and aRenderingContext might have some transform in it
+  // We need a *reference* rendering context (not one that might have a
+  // transform), so we don't have a rendering context argument.
   // XXX get the block and line passed to us somehow! This is slow!
   gfxSkipCharsIterator iter = EnsureTextRun(nsTextFrame::eInflated);
   if (!mTextRun)
     return false;
 
   PropertyProvider provider(this, iter, nsTextFrame::eInflated);
   // Trim trailing whitespace
   provider.InitializeForDisplay(true);
 
   PRUint32 startOffset = provider.GetStart().GetSkippedOffset();
   PRUint32 maxLength = ComputeTransformedLength(provider);
-  return MeasureCharClippedText(aCtx, provider, aLeftEdge, aRightEdge,
+  return MeasureCharClippedText(provider, aLeftEdge, aRightEdge,
                                 &startOffset, &maxLength,
                                 aSnappedLeftEdge, aSnappedRightEdge);
 }
 
 static PRUint32 GetClusterLength(gfxTextRun* aTextRun,
                                  PRUint32    aStartOffset,
                                  PRUint32    aMaxLength,
                                  bool        aIsRTL)
@@ -5309,18 +5308,17 @@ static PRUint32 GetClusterLength(gfxText
       break;
     }
     ++clusterLength;
   }
   return clusterLength;
 }
 
 bool
-nsTextFrame::MeasureCharClippedText(gfxContext* aCtx,
-                                    PropertyProvider& aProvider,
+nsTextFrame::MeasureCharClippedText(PropertyProvider& aProvider,
                                     nscoord aLeftEdge, nscoord aRightEdge,
                                     PRUint32* aStartOffset,
                                     PRUint32* aMaxLength,
                                     nscoord*  aSnappedLeftEdge,
                                     nscoord*  aSnappedRightEdge)
 {
   *aSnappedLeftEdge = 0;
   *aSnappedRightEdge = 0;
@@ -5396,17 +5394,17 @@ nsTextFrame::PaintText(nsRenderingContex
   const bool rtl = mTextRun->IsRightToLeft();
   const nscoord frameWidth = GetSize().width;
   gfxPoint framePt(aPt.x, aPt.y);
   gfxPoint textBaselinePt(rtl ? gfxFloat(aPt.x + frameWidth) : framePt.x,
              nsLayoutUtils::GetSnappedBaselineY(this, ctx, aPt.y, mAscent));
   PRUint32 startOffset = provider.GetStart().GetSkippedOffset();
   PRUint32 maxLength = ComputeTransformedLength(provider);
   nscoord snappedLeftEdge, snappedRightEdge;
-  if (!MeasureCharClippedText(ctx, provider, aItem.mLeftEdge, aItem.mRightEdge,
+  if (!MeasureCharClippedText(provider, aItem.mLeftEdge, aItem.mRightEdge,
          &startOffset, &maxLength, &snappedLeftEdge, &snappedRightEdge)) {
     return;
   }
   textBaselinePt.x += rtl ? -snappedRightEdge : snappedLeftEdge;
   nsCharClipDisplayItem::ClipEdges clipEdges(aItem, snappedLeftEdge,
                                              snappedRightEdge);
   nsTextPaintStyle textPaintStyle(this);