added definition for websocket browser forwarder

features/ext/browser.go

@@ -0,0 +1,10 @@
+package ext
+
+import (
+	"io"
+	"net/http"
+)
+
+type BrowserForwarder interface {
+	DialWebsocket(url string, header http.Header) (io.ReadWriteCloser, error)
+}