Implement SetDefersLoading on content::URLLoaderClientImpl

content/child/resource_dispatcher.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.
 
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #include "content/child/resource_dispatcher.h"
 
 #include <utility>
 
@@ skipping 465 matching lines @@
 }
 
 void ResourceDispatcher::SetDefersLoading(int request_id, bool value) {
   PendingRequestInfo* request_info = GetPendingRequestInfo(request_id);
   if (!request_info) {
     DLOG(ERROR) << "unknown request";
     return;
   }
   if (value) {
     request_info->is_deferred = value;
+    if (request_info->url_loader_client)
+      request_info->url_loader_client->SetDefersLoading();
   } else if (request_info->is_deferred) {
     request_info->is_deferred = false;
 
+    if (request_info->url_loader_client)
+      request_info->url_loader_client->UnsetDefersLoading();
+
     FollowPendingRedirect(request_id, request_info);
 
     main_thread_task_runner_->PostTask(
         FROM_HERE, base::Bind(&ResourceDispatcher::FlushDeferredMessages,
                               weak_factory_.GetWeakPtr(), request_id));
   }
 }
 
 void ResourceDispatcher::DidChangePriority(int request_id,
                                            net::RequestPriority new_priority,
@@ skipping 47 matching lines @@
     IPC_MESSAGE_HANDLER(ResourceMsg_DataReceived, OnReceivedData)
     IPC_MESSAGE_HANDLER(ResourceMsg_DataDownloaded, OnDownloadedData)
     IPC_MESSAGE_HANDLER(ResourceMsg_RequestComplete, OnRequestComplete)
   IPC_END_MESSAGE_MAP()
 }
 
 void ResourceDispatcher::FlushDeferredMessages(int request_id) {
   PendingRequestInfo* request_info = GetPendingRequestInfo(request_id);
   if (!request_info || request_info->is_deferred)
     return;
+
+  if (request_info->url_loader)
+    request_info->url_loader_client->FlushDeferredMessages();

[kinuko, 2016/12/23 13:11:23]

Having two pending queues is confusing, it seems if we have url_loader should
resource_dispatcher's deferred_message_queue is empty, is that right?  If so
could we DCHECK it and return here?

[yhirano, 2016/12/26 05:08:35]

I've just noticed that |request_info| can be broken here (i.e., the cancelled
case). So I'm simply putting a return statement here.

+
   // Because message handlers could result in request_info being destroyed,
   // we need to work with a stack reference to the deferred queue.
   MessageQueue q;
   q.swap(request_info->deferred_message_queue);
   while (!q.empty()) {
     IPC::Message* m = q.front();
     q.pop_front();
     DispatchMessage(*m);
     delete m;
     // We need to find the request again in the list as it may have completed
@@ skipping 233 matching lines @@
     delete message;
   }
 }
 
 void ResourceDispatcher::SetResourceSchedulingFilter(
     scoped_refptr<ResourceSchedulingFilter> resource_scheduling_filter) {
   resource_scheduling_filter_ = resource_scheduling_filter;
 }
 
 }  // namespace content