PlzNavigate: properly update NavigationHandle for 204/205 and download responses

content/browser/loader/navigation_resource_handler.cc

 // Copyright 2014 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/navigation_resource_handler.h"
 
 #include <memory>
 
 #include "base/logging.h"
 #include "content/browser/loader/navigation_url_loader_impl_core.h"
@@ skipping 76 matching lines @@
   *defer = true;
   return true;
 }
 
 bool NavigationResourceHandler::OnResponseStarted(ResourceResponse* response,
                                                   bool* defer) {
   DCHECK(core_);
 
   ResourceRequestInfoImpl* info = GetRequestInfo();
 
-  // If the MimeTypeResourceHandler intercepted this request and converted it
-  // into a download, it will still call OnResponseStarted and immediately
-  // cancel. Ignore the call; OnReadCompleted will happen shortly.
-  //
-  // TODO(davidben): Move the dispatch out of MimeTypeResourceHandler. Perhaps
-  // all the way to the UI thread. Downloads, user certificates, etc., should be
-  // dispatched at the navigation layer.
-  if (info->IsDownload())
-    return true;
-
   StreamContext* stream_context =
       GetStreamContextForResourceContext(info->GetContext());
   writer_.InitializeStream(stream_context->registry(),
                            request()->url().GetOrigin());
 
   NetLogObserver::PopulateResponseInfo(request(), response);
 
   std::unique_ptr<NavigationData> cloned_data;
   if (resource_dispatcher_host_delegate_) {
     // Ask the embedder for a NavigationData instance.
     NavigationData* navigation_data =
         resource_dispatcher_host_delegate_->GetNavigationData(request());
 
     // Clone the embedder's NavigationData before moving it to the UI thread.
     if (navigation_data)
       cloned_data = navigation_data->Clone();
   }
 
   SSLStatus ssl_status;
   if (request()->ssl_info().cert.get()) {
     GetSSLStatusForRequest(request()->url(), request()->ssl_info(),
                            info->GetChildID(), &ssl_status);
   }
 
   core_->NotifyResponseStarted(response, writer_.stream()->CreateHandle(),
-                               ssl_status, std::move(cloned_data));
-  // Don't defer stream based requests. This includes requests initiated via
-  // mime type sniffing, etc.
+                               ssl_status, std::move(cloned_data),
+                               info->IsDownload());
+  // Don't defer stream based or download requests. This includes requests
+  // initiated via mime type sniffing, etc.
   // TODO(ananta)
   // Make sure that the requests go through the throttle checks. Currently this
   // does not work as the InterceptingResourceHandler is above us and hence it
   // does not expect the old handler to defer the request.
-  if (!info->is_stream())
+  if (!info->is_stream() && !info->IsDownload())

[clamy, 2016/11/25 10:46:00]

I think we should call DetachFromCore if the request is a download at this
point. Otherwise we may end up trying to cancel the request if the
NavigationURLLoader is deleted.

[yzshen1, 2016/11/28 22:03:59]

In practice it won't cause trouble because before returning to the message loop
this NavigationResourceHandler object will be destructed -> it will try to
notify the UI thread about the request failure -> when that task is run on the
UI thread, the NavigationURLLoaderImpl has already been destroyed so it is a
no-op.

I agree that it is better not to rely on that. Thanks for the suggestion!

     *defer = true;
   return true;
 }
 
 bool NavigationResourceHandler::OnWillStart(const GURL& url, bool* defer) {
   return true;
 }
 
 bool NavigationResourceHandler::OnWillRead(scoped_refptr<net::IOBuffer>* buf,
                                            int* buf_size,
@@ skipping 28 matching lines @@
   NOTREACHED();
 }
 
 void NavigationResourceHandler::DetachFromCore() {
   DCHECK(core_);
   core_->set_resource_handler(nullptr);
   core_ = nullptr;
 }
 
 }  // namespace content