Decouple URLRequestJob from URLRequestContext; access NetworkDelegate as a contructor parameter.

net/url_request/url_request.cc

 // 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.
 
 #include "net/url_request/url_request.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
@@ skipping 393 matching lines @@
 
 void URLRequest::set_delegate(Delegate* delegate) {
   delegate_ = delegate;
 }
 
 void URLRequest::Start() {
   g_url_requests_started = true;
   response_info_.request_time = Time::Now();
 
   // Only notify the delegate for the initial request.
-  if (context_ && context_->network_delegate()) {
+  if (context_->network_delegate()) {
     int error = context_->network_delegate()->NotifyBeforeURLRequest(
         this, before_request_callback_, &delegate_redirect_url_);
     if (error == net::ERR_IO_PENDING) {
       // Paused on the delegate, will invoke |before_request_callback_| later.
       SetBlockedOnDelegate();
     } else {
       BeforeRequestComplete(error);
     }
     return;
   }
@@ skipping 479 matching lines @@
       new base::debug::StackTrace(NULL, 0);
   *stack_trace_copy = stack_trace;
   stack_trace_.reset(stack_trace_copy);
 }
 
 const base::debug::StackTrace* URLRequest::stack_trace() const {
   return stack_trace_.get();
 }
 
 }  // namespace net