diff --git a/layout/forms/nsHTMLButtonControlFrame.cpp b/layout/forms/nsHTMLButtonControlFrame.cpp
index dcbad2247b7c..620a595795de 100644
--- a/layout/forms/nsHTMLButtonControlFrame.cpp
+++ b/layout/forms/nsHTMLButtonControlFrame.cpp
@@ -373,11 +373,12 @@ nsHTMLButtonControlFrame::SetAdditionalStyleContext(int32_t aIndex,
   mRenderer.SetStyleContext(aIndex, aStyleContext);
 }
 
-void 
+#ifdef DEBUG
+void
 nsHTMLButtonControlFrame::AppendFrames(ChildListID     aListID,
                                        nsFrameList&    aFrameList)
 {
-  NS_NOTREACHED("unsupported operation");
+  MOZ_CRASH("unsupported operation");
 }
 
 void
@@ -385,12 +386,13 @@ nsHTMLButtonControlFrame::InsertFrames(ChildListID     aListID,
                                        nsIFrame*       aPrevFrame,
                                        nsFrameList&    aFrameList)
 {
-  NS_NOTREACHED("unsupported operation");
+  MOZ_CRASH("unsupported operation");
 }
 
 void
 nsHTMLButtonControlFrame::RemoveFrame(ChildListID     aListID,
                                       nsIFrame*       aOldFrame)
 {
-  NS_NOTREACHED("unsupported operation");
+  MOZ_CRASH("unsupported operation");
 }
+#endif
diff --git a/layout/forms/nsHTMLButtonControlFrame.h b/layout/forms/nsHTMLButtonControlFrame.h
index b7289847b260..9b5ff920853c 100644
--- a/layout/forms/nsHTMLButtonControlFrame.h
+++ b/layout/forms/nsHTMLButtonControlFrame.h
@@ -51,15 +51,15 @@ public:
   virtual void SetAdditionalStyleContext(int32_t aIndex, 
                                          nsStyleContext* aStyleContext) MOZ_OVERRIDE;
  
+#ifdef DEBUG
   virtual void AppendFrames(ChildListID     aListID,
                             nsFrameList&    aFrameList) MOZ_OVERRIDE;
-
   virtual void InsertFrames(ChildListID     aListID,
                             nsIFrame*       aPrevFrame,
                             nsFrameList&    aFrameList) MOZ_OVERRIDE;
-
   virtual void RemoveFrame(ChildListID     aListID,
                            nsIFrame*       aOldFrame) MOZ_OVERRIDE;
+#endif
 
 #ifdef ACCESSIBILITY
   virtual mozilla::a11y::AccType AccessibleType() MOZ_OVERRIDE;