diff --git a/dom/file/ipc/IPCBlobInputStreamChild.cpp b/dom/file/ipc/IPCBlobInputStreamChild.cpp
index 96742b931c83..441c78ac67db 100644
--- a/dom/file/ipc/IPCBlobInputStreamChild.cpp
+++ b/dom/file/ipc/IPCBlobInputStreamChild.cpp
@@ -10,6 +10,9 @@
 #include "WorkerHolder.h"
 
 namespace mozilla {
+
+using namespace workers;
+
 namespace dom {
 
 namespace {