Make SyncLoad result handling pluggable

content/browser/loader/sync_resource_handler.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/sync_resource_handler.h"
 
 #include "base/logging.h"
 #include "content/browser/loader/netlog_observer.h"
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 #include "content/browser/loader/resource_message_filter.h"
 #include "content/browser/loader/resource_request_info_impl.h"
 #include "content/common/resource_messages.h"
 #include "content/public/browser/resource_dispatcher_host_delegate.h"
 #include "content/public/browser/resource_request_info.h"
 #include "net/base/io_buffer.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/redirect_info.h"
 
 namespace content {
 
 SyncResourceHandler::SyncResourceHandler(
     net::URLRequest* request,
-    IPC::Message* result_message,
+    const SyncLoadResultCallback& result_handler,
     ResourceDispatcherHostImpl* resource_dispatcher_host)
     : ResourceHandler(request),
       read_buffer_(new net::IOBuffer(kReadBufSize)),
-      result_message_(result_message),
+      result_handler_(result_handler),
       rdh_(resource_dispatcher_host),
       total_transfer_size_(0) {
   result_.final_url = request->url();
 }
 
 SyncResourceHandler::~SyncResourceHandler() {
-  if (result_message_) {
-    result_message_->set_reply_error();
-    ResourceMessageFilter* filter = GetFilter();
-    // If the filter doesn't exist at this point, the process has died and isn't
-    // waiting for the result message anymore.
-    if (filter)
-      filter->Send(result_message_);
-  }
+  if (result_handler_)
+    result_handler_.Run(nullptr);

[yhirano, 2016/10/05 08:49:53]

This nullptr is corresponding to L427 in resource_dispatcher_host_impl.cc but
its relationship is not obvious. Some comments in ResourceDispatcherHostImpl
would be helpful, I think.

[tzik, 2016/10/06 12:52:03]

Done.

 }
 
 bool SyncResourceHandler::OnRequestRedirected(
     const net::RedirectInfo& redirect_info,
     ResourceResponse* response,
     bool* defer) {
   if (rdh_->delegate()) {
     rdh_->delegate()->OnRequestRedirected(
         redirect_info.new_url, request(), GetRequestInfo()->GetContext(),
         response);
@@ skipping 55 matching lines @@
 bool SyncResourceHandler::OnReadCompleted(int bytes_read, bool* defer) {
   if (!bytes_read)
     return true;
   result_.data.append(read_buffer_->data(), bytes_read);
   return true;
 }
 
 void SyncResourceHandler::OnResponseCompleted(
     const net::URLRequestStatus& status,
     bool* defer) {
   ResourceMessageFilter* filter = GetFilter();

[yhirano, 2016/10/05 08:49:53]

This is not used.

[tzik, 2016/10/06 12:52:03]

Done.

   if (!filter)
     return;
 
   result_.error_code = status.error();
 
   int total_transfer_size = request()->GetTotalReceivedBytes();
   result_.encoded_data_length = total_transfer_size_ + total_transfer_size;
   result_.encoded_body_length = request()->GetRawBodyBytes();
 
-  ResourceHostMsg_SyncLoad::WriteReplyParams(result_message_, result_);
-  filter->Send(result_message_);
-  result_message_ = NULL;
+  result_handler_.Run(&result_);
+  result_handler_.Reset();

[mmenke, 2016/10/05 15:21:33]

base::ResetAndReturn(result_handler_).Run?

[tzik, 2016/10/06 12:52:03]

Done.

   return;
 }
 
 void SyncResourceHandler::OnDataDownloaded(int bytes_downloaded) {
   // Sync requests don't involve ResourceMsg_DataDownloaded messages
   // being sent back to renderers as progress is made.
 }
 
 }  // namespace content