diff --git a/vendor/golang.org/x/oauth2/internal/client_appengine.go b/vendor/golang.org/x/oauth2/internal/client_appengine.go
new file mode 100644
index 0000000..7434871
--- /dev/null
+++ b/vendor/golang.org/x/oauth2/internal/client_appengine.go
@@ -0,0 +1,13 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build appengine
+
+package internal
+
+import "google.golang.org/appengine/urlfetch"
+
+func init() {
+	appengineClientHook = urlfetch.Client
+}