Adds the new URLRequest::OnBeforeNetworkStart hook to the

content/browser/loader/resource_loader.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 "content/browser/loader/resource_loader.h"
 
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/time/time.h"
@@ skipping 271 matching lines @@
       weak_ptr_factory_.GetWeakPtr(),
       info->GetGlobalRequestID(),
       info->GetResourceType(),
       request_->url(),
       render_process_id,
       render_frame_id,
       ssl_info,
       fatal);
 }
 
+void ResourceLoader::OnBeforeNetworkStart(net::URLRequest* unused,
+                                          bool* defer) {
+  DCHECK_EQ(request_.get(), unused);
+
+  // Give the handler a chance to delay the URLRequest from using the network.
+  if (!handler_->OnBeforeNetworkStart(
+           GetRequestInfo()->GetRequestID(), request_->url(), defer)) {
+    Cancel();
+    return;
+  } else if (*defer) {
+    deferred_stage_ = DEFERRED_NETWORK_START;
+  }
+}
+
 void ResourceLoader::OnResponseStarted(net::URLRequest* unused) {
   DCHECK_EQ(request_.get(), unused);
 
   VLOG(1) << "OnResponseStarted: " << request_->url().spec();
 
   // The CanLoadPage check should take place after any server redirects have
   // finished, at the point in time that we know a page will commit in the
   // renderer process.
   ResourceRequestInfoImpl* info = GetRequestInfo();
   ChildProcessSecurityPolicyImpl* policy =
@@ skipping 82 matching lines @@
 
   DeferredStage stage = deferred_stage_;
   deferred_stage_ = DEFERRED_NONE;
   switch (stage) {
     case DEFERRED_NONE:
       NOTREACHED();
       break;
     case DEFERRED_START:
       StartRequestInternal();
       break;
+    case DEFERRED_NETWORK_START:
+      request_->ResumeNetworkStart();
+      break;
     case DEFERRED_REDIRECT:
       request_->FollowDeferredRedirect();
       break;
     case DEFERRED_READ:
       base::MessageLoop::current()->PostTask(
           FROM_HERE,
           base::Bind(&ResourceLoader::ResumeReading,
                      weak_ptr_factory_.GetWeakPtr()));
       break;
     case DEFERRED_FINISH:
@@ skipping 255 matching lines @@
       case net::URLRequestStatus::FAILED:
         status = STATUS_UNDEFINED;
         break;
     }
 
     UMA_HISTOGRAM_ENUMERATION("Net.Prefetch.Pattern", status, STATUS_MAX);
   }
 }
 
 }  // namespace content