net: Socket pools prioritize requests with ignore_limits

net/socket/client_socket_pool_base.h

 // Copyright (c) 2012 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.
 //
 // A ClientSocketPoolBase is used to restrict the number of sockets open at
 // a time.  It also maintains a list of idle persistent sockets for reuse.
 // Subclasses of ClientSocketPool should compose ClientSocketPoolBase to handle
 // the core logic of (1) restricting the number of active (connected or
 // connecting) sockets per "group" (generally speaking, the hostname), (2)
 // maintaining a per-group list of idle, persistent sockets for reuse, and (3)
@@ skipping 425 matching lines @@
     CallbackResultPair(const CompletionCallback& callback_in, int result_in);
     ~CallbackResultPair();
 
     CompletionCallback callback;
     int result;
   };
 
   typedef std::map<const ClientSocketHandle*, CallbackResultPair>
       PendingCallbackMap;
 
+  // Inserts the request into the queue based on order they will receive
+  // sockets. Sockets which ignore the socket pool limits are first. Then
+  // requests are sorted by priority, with higher priorities closer to the
+  // front. Older requests are prioritized over requests of equal priority.
   static void InsertRequestIntoQueue(const Request* r,
                                      RequestQueue* pending_requests);
   static const Request* RemoveRequestFromQueue(const RequestQueue::iterator& it,
                                                Group* group);
 
   Group* GetOrCreateGroup(const std::string& group_name);
   void RemoveGroup(const std::string& group_name);
   void RemoveGroup(GroupMap::iterator it);
 
   // Called when the number of idle sockets changes.
@@ skipping 344 matching lines @@
   // Histograms for the pool
   ClientSocketPoolHistograms* const histograms_;
   internal::ClientSocketPoolBaseHelper helper_;
 
   DISALLOW_COPY_AND_ASSIGN(ClientSocketPoolBase);
 };
 
 }  // namespace net
 
 #endif  // NET_SOCKET_CLIENT_SOCKET_POOL_BASE_H_