No bug - Fix buildwarning about nsHTMLDocument::GetPlugins; r=bz

content/html/document/src/nsHTMLDocument.h

@@ -72,6 +72,7 @@ class nsHTMLDocument : public nsDocument,
 {
 public:
   using nsDocument::SetDocumentURI;
+  using nsDocument::GetPlugins;
 
   nsHTMLDocument();
   virtual nsresult Init();