Allows deferral of a URLRequest just before talking to the network, at

net/http/http_network_transaction.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.
 
 #ifndef NET_HTTP_HTTP_NETWORK_TRANSACTION_H_
 #define NET_HTTP_HTTP_NETWORK_TRANSACTION_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 54 matching lines @@
   virtual int64 GetTotalReceivedBytes() const OVERRIDE;
   virtual void DoneReading() OVERRIDE {}
   virtual const HttpResponseInfo* GetResponseInfo() const OVERRIDE;
   virtual LoadState GetLoadState() const OVERRIDE;
   virtual UploadProgress GetUploadProgress() const OVERRIDE;
   virtual bool GetLoadTimingInfo(
       LoadTimingInfo* load_timing_info) const OVERRIDE;
   virtual void SetPriority(RequestPriority priority) OVERRIDE;
   virtual void SetWebSocketHandshakeStreamCreateHelper(
       WebSocketHandshakeStreamBase::CreateHelper* create_helper) OVERRIDE;
+  virtual void SetBeforeNetworkStartCallback(
+      const BeforeNetworkStartCallback& callback) OVERRIDE;
+  virtual int ResumeNetworkStart() OVERRIDE;
 
   // HttpStreamRequest::Delegate methods:
   virtual void OnStreamReady(const SSLConfig& used_ssl_config,
                              const ProxyInfo& used_proxy_info,
                              HttpStreamBase* stream) OVERRIDE;
   virtual void OnWebSocketHandshakeStreamReady(
       const SSLConfig& used_ssl_config,
       const ProxyInfo& used_proxy_info,
       WebSocketHandshakeStreamBase* stream) OVERRIDE;
   virtual void OnStreamFailed(int status,
@@ skipping 25 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionTest,
                            WindowUpdateOverflow);
   FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionTest,
                            FlowControlStallResume);
   FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionTest,
                            FlowControlStallResumeAfterSettings);
   FRIEND_TEST_ALL_PREFIXES(SpdyNetworkTransactionTest,
                            FlowControlNegativeSendWindowSize);
 
   enum State {
+    STATE_NOTIFY_BEFORE_CREATE_STREAM,
     STATE_CREATE_STREAM,
     STATE_CREATE_STREAM_COMPLETE,
     STATE_INIT_STREAM,
     STATE_INIT_STREAM_COMPLETE,
     STATE_GENERATE_PROXY_AUTH_TOKEN,
     STATE_GENERATE_PROXY_AUTH_TOKEN_COMPLETE,
     STATE_GENERATE_SERVER_AUTH_TOKEN,
     STATE_GENERATE_SERVER_AUTH_TOKEN_COMPLETE,
     STATE_INIT_REQUEST_BODY,
     STATE_INIT_REQUEST_BODY_COMPLETE,
@@ skipping 15 matching lines @@
   void DoCallback(int result);
   void OnIOComplete(int result);
 
   // Runs the state transition loop.
   int DoLoop(int result);
 
   // Each of these methods corresponds to a State value.  Those with an input
   // argument receive the result from the previous state.  If a method returns
   // ERR_IO_PENDING, then the result from OnIOComplete will be passed to the
   // next state method as the result arg.
+  int DoNotifyBeforeCreateStream();
   int DoCreateStream();
   int DoCreateStreamComplete(int result);
   int DoInitStream();
   int DoInitStreamComplete(int result);
   int DoGenerateProxyAuthToken();
   int DoGenerateProxyAuthTokenComplete(int result);
   int DoGenerateServerAuthToken();
   int DoGenerateServerAuthTokenComplete(int result);
   int DoInitRequestBody();
   int DoInitRequestBodyComplete(int result);
@@ skipping 160 matching lines @@
 
   // True when the tunnel is in the process of being established - we can't
   // read from the socket until the tunnel is done.
   bool establishing_tunnel_;
 
   // The helper object to use to create WebSocketHandshakeStreamBase
   // objects. Only relevant when establishing a WebSocket connection.
   WebSocketHandshakeStreamBase::CreateHelper*
       websocket_handshake_stream_base_create_helper_;
 
+  BeforeNetworkStartCallback before_network_start_callback_;
+
   DISALLOW_COPY_AND_ASSIGN(HttpNetworkTransaction);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_NETWORK_TRANSACTION_H_