diff --git a/dom/webidl/DeviceStorage.webidl b/dom/webidl/DeviceStorage.webidl
index 4c4c32afa61..9016b02def1 100644
--- a/dom/webidl/DeviceStorage.webidl
+++ b/dom/webidl/DeviceStorage.webidl
@@ -82,6 +82,9 @@ interface DeviceStorage : EventTarget {
   // for storing new files.
   readonly attribute boolean default;
 
+  // Indicates if the storage area denoted by storageName is removable
+  readonly attribute boolean isRemovable;
+
   [NewObject, Throws]
   // XXXbz what type does this really return?
   Promise<any> getRoot();