proxy: move from exp/proxy

This change copies exp/proxy to go.net without any code changes. A
followup CL will remove exp/proxy.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6449097
diff --git a/proxy/direct.go b/proxy/direct.go
new file mode 100644
index 0000000..4c5ad88
--- /dev/null
+++ b/proxy/direct.go
@@ -0,0 +1,18 @@
+// Copyright 2011 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.
+
+package proxy
+
+import (
+	"net"
+)
+
+type direct struct{}
+
+// Direct is a direct proxy: one that makes network connections directly.
+var Direct = direct{}
+
+func (direct) Dial(network, addr string) (net.Conn, error) {
+	return net.Dial(network, addr)
+}