Update from https://crrev.com/304121

net/websockets/websocket_throttle.h

-// Copyright (c) 2011 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.
-
-#ifndef NET_WEBSOCKETS_WEBSOCKET_THROTTLE_H_
-#define NET_WEBSOCKETS_WEBSOCKET_THROTTLE_H_
-
-#include <deque>
-#include <map>
-#include <set>
-#include <string>
-
-#include "net/base/ip_endpoint.h"
-#include "net/base/net_export.h"
-
-template <typename T> struct DefaultSingletonTraits;
-
-namespace net {
-
-class SocketStream;
-class WebSocketJob;
-
-// SocketStreamThrottle for WebSocket protocol.
-// Implements the client-side requirements in the spec.
-// http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol
-// 4.1 Handshake
-//   1.   If the user agent already has a Web Socket connection to the
-//        remote host (IP address) identified by /host/, even if known by
-//        another name, wait until that connection has been established or
-//        for that connection to have failed.
-class NET_EXPORT_PRIVATE WebSocketThrottle {
- public:
-  // Returns the singleton instance.
-  static WebSocketThrottle* GetInstance();
-
-  // Puts |job| in |queue_| and queues for the destination addresses
-  // of |job|.
-  // If other job is using the same destination address, set |job| waiting.
-  //
-  // Returns true if successful. If the number of pending jobs will exceed
-  // the limit, does nothing and returns false.
-  bool PutInQueue(WebSocketJob* job);
-
-  // Removes |job| from |queue_| and queues for the destination addresses
-  // of |job|, and then wakes up jobs that can now resume establishing a
-  // connection.
-  void RemoveFromQueue(WebSocketJob* job);
-
- private:
-  typedef std::deque<WebSocketJob*> ConnectingQueue;
-  typedef std::map<IPEndPoint, ConnectingQueue> ConnectingAddressMap;
-
-  WebSocketThrottle();
-  ~WebSocketThrottle();
-  friend struct DefaultSingletonTraits<WebSocketThrottle>;
-
-  // Examines if any of the given jobs can resume establishing a connection. If
-  // for all per-address queues for each resolved addresses
-  // (job->address_list()) of a job, the job is at the front of the queues, the
-  // job can resume establishing a connection, so wakes up the job.
-  void WakeupSocketIfNecessary(
-      const std::set<WebSocketJob*>& wakeup_candidates);
-
-  // Key: string of host's address.  Value: queue of sockets for the address.
-  ConnectingAddressMap addr_map_;
-
-  // Queue of sockets for websockets in opening state.
-  ConnectingQueue queue_;
-
-  DISALLOW_COPY_AND_ASSIGN(WebSocketThrottle);
-};
-
-}  // namespace net
-
-#endif  // NET_WEBSOCKETS_WEBSOCKET_THROTTLE_H_