<button> should be a containing block. Bug 180301, r=jkeiser, sr=dbaron

layout/forms/nsHTMLButtonControlFrame.cpp

@@ -621,6 +621,14 @@ nsHTMLButtonControlFrame::Reflow(nsIPresContext* aPresContext,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsHTMLButtonControlFrame::IsPercentageBase(PRBool& aBase) const
+{
+  aBase = PR_TRUE;
+  return NS_OK;
+}
+
+
 PRIntn
 nsHTMLButtonControlFrame::GetSkipSides() const
 {

layout/forms/nsHTMLButtonControlFrame.h

@@ -87,6 +87,8 @@ public:
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus&          aStatus);
 
+  NS_IMETHOD IsPercentageBase(PRBool& aBase) const;
+  
   NS_IMETHOD HandleEvent(nsIPresContext* aPresContext, 
                          nsGUIEvent* aEvent,
                          nsEventStatus* aEventStatus);

layout/html/forms/src/nsHTMLButtonControlFrame.cpp

@@ -621,6 +621,14 @@ nsHTMLButtonControlFrame::Reflow(nsIPresContext* aPresContext,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsHTMLButtonControlFrame::IsPercentageBase(PRBool& aBase) const
+{
+  aBase = PR_TRUE;
+  return NS_OK;
+}
+
+
 PRIntn
 nsHTMLButtonControlFrame::GetSkipSides() const
 {

layout/html/forms/src/nsHTMLButtonControlFrame.h

@@ -87,6 +87,8 @@ public:
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus&          aStatus);
 
+  NS_IMETHOD IsPercentageBase(PRBool& aBase) const;
+  
   NS_IMETHOD HandleEvent(nsIPresContext* aPresContext, 
                          nsGUIEvent* aEvent,
                          nsEventStatus* aEventStatus);