Update from https://crrev.com/305340

net/websockets/websocket_handshake_challenge.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/websockets/websocket_handshake_challenge.h"
+
+#include "base/base64.h"
+#include "base/sha1.h"
+#include "net/websockets/websocket_handshake_constants.h"
+
+namespace net {
+
+std::string ComputeSecWebSocketAccept(const std::string& key) {
+  std::string accept;
+  std::string hash = base::SHA1HashString(key + websockets::kWebSocketGuid);
+  base::Base64Encode(hash, &accept);
+  return accept;
+}
+
+}  // namespace net