Reland 54771 (and 54795) To enable TCP Preconnection by default...

chrome/browser/net/preconnect.h

 // Copyright (c) 2006-2010 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 Preconnect instance maintains state while a TCP/IP connection is made, and
 // and then released into the pool of available connections for future use.
 
 #ifndef CHROME_BROWSER_NET_PRECONNECT_H_
 #define CHROME_BROWSER_NET_PRECONNECT_H_
 #pragma once
 
 #include "base/ref_counted.h"
 #include "chrome/browser/net/url_info.h"
 #include "net/base/completion_callback.h"
 #include "net/base/host_port_pair.h"
 #include "net/socket/client_socket_handle.h"
 #include "net/socket/tcp_client_socket_pool.h"
 #include "net/url_request/url_request_context.h"
 
 namespace chrome_browser_net {
 
-class Preconnect : public net::CompletionCallback {
+class Preconnect : public net::CompletionCallback,
+                   public base::RefCountedThreadSafe<Preconnect> {
  public:
   // Try to preconnect.  Typically motivated by OMNIBOX to reach search service.
   static void PreconnectOnUIThread(const GURL& url,
                                    UrlInfo::ResolutionMotivation motivation);
 
   // Try to preconnect.  Typically used by predictor when a subresource probably
   // needs a connection.
   static void PreconnectOnIOThread(const GURL& url,
                                    UrlInfo::ResolutionMotivation motivation);
 
   static void SetPreconnectDespiteProxy(bool status) {
     preconnect_despite_proxy_ = status;
   }
 
  private:
-  Preconnect() {}
+  friend class base::RefCountedThreadSafe<Preconnect>;
 
-  // Supply an instance that could have been used in an IO callback, but will
-  // never actually be used (because we reset the connection so quickly).
-  static Preconnect* callback_instance_;
+  explicit Preconnect(UrlInfo::ResolutionMotivation motivation)
+      : motivation_(motivation) {
+  }
+  ~Preconnect();
+
+  // Request actual connection.
+  void Connect(const GURL& url);
 
   // IO Callback which whould be performed when the connection is established.
   virtual void RunWithParams(const Tuple1<int>& params);
 
   // Preconnections are currently conservative, and do nothing if there is a
   // chance that a proxy may be used.  This boolean allows proxy settings to
   // be ignored (presumably because a user knows that the proxy won't be doing
   // much work anway).
   static bool preconnect_despite_proxy_;
 
+  // The handle holding the request. We need this so that we can mark the
+  // request as speculative when an actual socket is bound to it.
+  net::ClientSocketHandle handle_;
+
+  // Generally either LEARNED_REFERAL_MOTIVATED or OMNIBOX_MOTIVATED to indicate
+  // why we were trying to do a preconnection.
+  const UrlInfo::ResolutionMotivation motivation_;
+
+
   DISALLOW_COPY_AND_ASSIGN(Preconnect);
 };
 }  // chrome_browser_net
 
 #endif  // CHROME_BROWSER_NET_PRECONNECT_H_