Bug 349899 --enable-xpctools still fails during XULrunner build

Fixing regression from Bug 285404 faster access to XPConnectWrappedNative's native pointer
nsIXPConnect now *uses* classes from nsCOMPtr.h so it should pull in the file instead of expecting poor confused consumers to do so.
r=bsmedberg

js/src/xpconnect/idl/nsIXPConnect.idl

@@ -215,6 +215,8 @@ public:
 };
 
 %{C++
+#include "nsCOMPtr.h"
+
 inline
 const nsQueryInterface
 do_QueryWrappedNative(nsIXPConnectWrappedNative *aWrappedNative)