net: Add Life of a URLRequest documentation.

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/location.h"
 #include "base/metrics/histogram.h"
 #include "base/profiler/scoped_tracker.h"
@@ skipping 231 matching lines @@
   }
 
   delegate_->DidReceiveRedirect(this, redirect_info.new_url);
 
   if (delegate_->HandleExternalProtocol(this, redirect_info.new_url)) {
     // The request is complete so we can remove it.
     CancelAndIgnore();
     return;
   }
 
+    *defer = true;
+    deferred_stage_ = DEFERRED_REDIRECT;
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(&ResourceLoader::Resume,
+                              weak_ptr_factory_.GetWeakPtr()));
+    Cancel();
+    if(true)
+      return;

[xunjieli, 2015/07/10 20:32:25]

I don't understand why this block is almost identical as the one added on line
267, and why it is in this CL. The indentation does not look right. Should it be
in a separate CL?

[mmenke, 2015/07/10 21:37:31]

Hrm...This shouldn't be in this CL.  Was investigating another issue, and forgot
to remove the test code before committing.

+
   scoped_refptr<ResourceResponse> response(new ResourceResponse());
   PopulateResourceResponse(info, request_.get(), response.get());
   if (!handler_->OnRequestRedirected(redirect_info, response.get(), defer)) {
     Cancel();
   } else if (*defer) {
     deferred_stage_ = DEFERRED_REDIRECT;  // Follow redirect when resumed.
+  } else {
+    *defer = true;
+    deferred_stage_ = DEFERRED_REDIRECT;
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(&ResourceLoader::Resume,
+                              weak_ptr_factory_.GetWeakPtr()));
+    Cancel();
   }
 }
 
 void ResourceLoader::OnAuthRequired(net::URLRequest* unused,
                                     net::AuthChallengeInfo* auth_info) {
   DCHECK_EQ(request_.get(), unused);
 
   ResourceRequestInfoImpl* info = GetRequestInfo();
   if (info->do_not_prompt_for_login()) {
     request_->CancelAuth();
@@ skipping 499 matching lines @@
       case net::URLRequestStatus::FAILED:
         status = STATUS_UNDEFINED;
         break;
     }
 
     UMA_HISTOGRAM_ENUMERATION("Net.Prefetch.Pattern", status, STATUS_MAX);
   }
 }
 
 }  // namespace content