--- a/layout/forms/nsProgressFrame.cpp
+++ b/layout/forms/nsProgressFrame.cpp
@@ -274,16 +274,38 @@ nsProgressFrame::ComputeAutoSize(nsRende
     autoSize.height *= 10; // 10em
   } else {
     autoSize.width *= 10; // 10em
   }
 
   return autoSize;
 }
 
+nscoord
+nsProgressFrame::GetMinWidth(nsRenderingContext *aRenderingContext)
+{
+  nsRefPtr<nsFontMetrics> fontMet;
+  NS_ENSURE_SUCCESS(
+      nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fontMet)), 0);
+
+  nscoord minWidth = fontMet->Font().size; // 1em
+
+  if (GetStyleDisplay()->mOrient == NS_STYLE_ORIENT_HORIZONTAL) {
+    minWidth *= 10; // 10em
+  }
+
+  return minWidth;
+}
+
+nscoord
+nsProgressFrame::GetPrefWidth(nsRenderingContext *aRenderingContext)
+{
+  return GetMinWidth(aRenderingContext);
+}
+
 bool
 nsProgressFrame::ShouldUseNativeStyle() const
 {
   // Use the native style if these conditions are satisfied:
   // - both frames use the native appearance;
   // - neither frame has author specified rules setting the border or the
   //   background.
   return GetStyleDisplay()->mAppearance == NS_THEME_PROGRESSBAR &&

--- a/layout/forms/nsProgressFrame.h
+++ b/layout/forms/nsProgressFrame.h
@@ -79,16 +79,19 @@ public:
                               nsIAtom* aAttribute,
                               PRInt32  aModType);
 
   virtual nsSize ComputeAutoSize(nsRenderingContext *aRenderingContext,
                                  nsSize aCBSize, nscoord aAvailableWidth,
                                  nsSize aMargin, nsSize aBorder,
                                  nsSize aPadding, PRBool aShrinkWrap);
 
+  virtual nscoord GetMinWidth(nsRenderingContext *aRenderingContext);
+  virtual nscoord GetPrefWidth(nsRenderingContext *aRenderingContext);
+
   virtual PRBool IsFrameOfType(PRUint32 aFlags) const
   {
     return nsHTMLContainerFrame::IsFrameOfType(aFlags &
       ~(nsIFrame::eReplaced | nsIFrame::eReplacedContainsBlock));
   }
 
   /**
    * Returns whether the frame and its child should use the native style.

--- a/layout/reftests/forms/progress/reftest.list
+++ b/layout/reftests/forms/progress/reftest.list
@@ -17,8 +17,9 @@
 
 # The following test is disabled but kept in the repository because the
 # transformations will not behave exactly the same for <progress> and two divs.
 # However, it would be possible to manually check those.
 # == transformations.html transformations-ref.html
 
 # Tests for bugs:
 == block-invalidate.html block-invalidate-ref.html
+== in-cells.html in-cells-ref.html