network service: pass PlzNavigate resulting data via mojo data pipe

content/child/resource_dispatcher.cc

Index: content/child/resource_dispatcher.cc
diff --git a/content/child/resource_dispatcher.cc b/content/child/resource_dispatcher.cc
index 50254c17507fbfab7e8439b911aefe9250d2a4ee..4484df9e30a3236d7084774c30afbec7d6cbf2cb 100644
--- a/content/child/resource_dispatcher.cc
+++ b/content/child/resource_dispatcher.cc
@@ -620,7 +620,8 @@ int ResourceDispatcher::StartAsync(
     const url::Origin& frame_origin,
     std::unique_ptr<RequestPeer> peer,
     blink::WebURLRequest::LoadingIPCType ipc_type,
-    mojom::URLLoaderFactory* url_loader_factory) {
+    mojom::URLLoaderFactory* url_loader_factory,
+    mojo::ScopedDataPipeConsumerHandle consumer_handle) {
   CheckSchemeForReferrerPolicy(*request);
 
   // Compute a unique request_id for this renderer process.
@@ -634,6 +635,21 @@ int ResourceDispatcher::StartAsync(
                                                         loading_task_runner);
   }
 
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner =
+      loading_task_runner ? loading_task_runner : main_thread_task_runner_;
+
+  if (consumer_handle.is_valid()) {
+    pending_requests_[request_id]->url_loader_client =
+        base::MakeUnique<URLLoaderClientImpl>(request_id, this, task_runner);
+
+    task_runner->PostTask(FROM_HERE,
+                          base::Bind(&ResourceDispatcher::ContinueForNavigation,
+                                     weak_factory_.GetWeakPtr(), request_id,
+                                     base::Passed(std::move(consumer_handle))));
+
+    return request_id;
+  }
+
   if (ipc_type == blink::WebURLRequest::LoadingIPCType::kMojo) {
     scoped_refptr<base::SingleThreadTaskRunner> task_runner =
         loading_task_runner ? loading_task_runner : main_thread_task_runner_;
@@ -735,6 +751,36 @@ base::TimeTicks ResourceDispatcher::ConsumeIOTimestamp() {
   return result;
 }
 
+void ResourceDispatcher::ContinueForNavigation(
+    int request_id,
+    mojo::ScopedDataPipeConsumerHandle consumer_handle) {
+  PendingRequestInfo* request_info = GetPendingRequestInfo(request_id);
+  if (!request_info)
+    return;
+
+  URLLoaderClientImpl* client_ptr = request_info->url_loader_client.get();
+
+  // Short circuiting call to OnReceivedResponse to immediately start
+  // the request. ResourceResponseHead can be empty here because we
+  // pull the StreamOverride's one in
+  // WebURLLoaderImpl::Context::OnReceivedResponse.
+  client_ptr->OnReceiveResponse(ResourceResponseHead(),
+                                mojom::DownloadedTempFilePtr());
+  // Start streaming now.
+  client_ptr->OnStartLoadingResponseBody(std::move(consumer_handle));
+
+  // Call OnComplete now too, as it won't get called on the client.
+  // TODO(kinuko): Fill this properly.
+  ResourceRequestCompletionStatus completion_status;
+  completion_status.error_code = net::OK;
+  completion_status.was_ignored_by_handler = false;
+  completion_status.exists_in_cache = false;
+  completion_status.completion_time = base::TimeTicks::Now();
+  completion_status.encoded_data_length = -1;
+  completion_status.encoded_body_length = -1;
+  client_ptr->OnComplete(completion_status);
+}
+
 // static
 bool ResourceDispatcher::IsResourceDispatcherMessage(
     const IPC::Message& message) {