Give HTMLButtonControlFrames their own frame type. Bug 335419, r+sr=dbaron

layout/forms/nsHTMLButtonControlFrame.cpp

@@ -71,6 +71,7 @@
 #include "nsIAccessibilityService.h"
 #endif
 #include "nsDisplayList.h"
+#include "nsLayoutAtoms.h"
 
 nsIFrame*
 NS_NewHTMLButtonControlFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
@@ -155,6 +156,12 @@ NS_IMETHODIMP nsHTMLButtonControlFrame::GetAccessible(nsIAccessible** aAccessibl
 }
 #endif
 
+nsIAtom*
+nsHTMLButtonControlFrame::GetType() const
+{
+  return nsLayoutAtoms::HTMLButtonControlFrame;
+}
+
 PRBool
 nsHTMLButtonControlFrame::IsReset(PRInt32 type)
 {