[Devtools] Allow User-Agent header override for Websockets

net/websockets/websocket_stream.h

Index: net/websockets/websocket_stream.h
diff --git a/net/websockets/websocket_stream.h b/net/websockets/websocket_stream.h
index accbf89b255a6012f403e9eef3826fd0da173619..28c9085150688d92594b6cf2100fb32fdc78d13e 100644
--- a/net/websockets/websocket_stream.h
+++ b/net/websockets/websocket_stream.h
@@ -108,6 +108,7 @@ class NET_EXPORT_PRIVATE WebSocketStream {
       const GURL& socket_url,
       const std::vector<std::string>& requested_subprotocols,
       const url::Origin& origin,
+      const std::string& additional_headers,
       URLRequestContext* url_request_context,
       const BoundNetLog& net_log,
       std::unique_ptr<ConnectDelegate> connect_delegate);
@@ -223,6 +224,7 @@ CreateAndConnectStreamForTesting(
     const GURL& socket_url,
     std::unique_ptr<WebSocketHandshakeStreamCreateHelper> create_helper,
     const url::Origin& origin,
+    const std::string& additional_headers,
     URLRequestContext* url_request_context,
     const BoundNetLog& net_log,
     std::unique_ptr<WebSocketStream::ConnectDelegate> connect_delegate,