Make SyncLoad result handling pluggable

content/browser/loader/sync_resource_handler.cc

Index: content/browser/loader/sync_resource_handler.cc
diff --git a/content/browser/loader/sync_resource_handler.cc b/content/browser/loader/sync_resource_handler.cc
index 47991f5fe248acc2114d71b914a537af7f9c5729..ee7361f7c350654866af842f27e91ace10517bc1 100644
--- a/content/browser/loader/sync_resource_handler.cc
+++ b/content/browser/loader/sync_resource_handler.cc
@@ -20,25 +20,19 @@ 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(
@@ -124,9 +118,8 @@ void SyncResourceHandler::OnResponseCompleted(
   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;
 }