Bug 1402180 - Remove nsIDOMHTMLAreaElement; r=bz

Removes the XPCOM interface for nsIDOMHTMLAreaElement, replacing it
with binding class usage.

MozReview-Commit-ID: IaX4JFTPZn6

accessible/html/HTMLImageMapAccessible.cpp

@@ -13,11 +13,11 @@
 #include "nsIDOMHTMLCollection.h"
 #include "nsIServiceManager.h"
 #include "nsIDOMElement.h"
-#include "nsIDOMHTMLAreaElement.h"
 #include "nsIFrame.h"
 #include "nsImageFrame.h"
 #include "nsImageMap.h"
 #include "nsIURI.h"
+#include "mozilla/dom/HTMLAreaElement.h"
 
 using namespace mozilla::a11y;
 
@@ -168,7 +168,7 @@ HTMLAreaAccessible::Description(nsString& aDescription)
   aDescription.Truncate();
 
   // Still to do - follow IE's standard here
-  nsCOMPtr<nsIDOMHTMLAreaElement> area(do_QueryInterface(mContent));
+  RefPtr<HTMLAreaElement> area = HTMLAreaElement::FromContentOrNull(mContent);
   if (area)
     area->GetShape(aDescription);
 }