Implement upload progress handling in Mojo loading

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 89a604da2ca3f47c1bd89a4b333fad4a76b9e8d0..f71da48d5c4a481cae46fb0304c4e08a6ba6e663 100644
--- a/content/child/resource_dispatcher.cc
+++ b/content/child/resource_dispatcher.cc
@@ -114,6 +114,14 @@ class URLLoaderClientImpl final : public mojom::URLLoaderClient {
         ResourceMsg_DataDownloaded(request_id_, data_len, encoded_data_len));
   }
 
+  void OnUploadProgress(int64_t current_position,
+                        int64_t total_size,
+                        const base::Closure& ack_callback) override {
+    resource_dispatcher_->OnMessageReceived(
+        ResourceMsg_UploadProgress(request_id_, current_position, total_size));
+    ack_callback.Run();
+  }
+
   void OnStartLoadingResponseBody(
       mojo::ScopedDataPipeConsumerHandle body) override {
     DCHECK(!body_consumer_);
@@ -230,8 +238,10 @@ void ResourceDispatcher::OnUploadProgress(int request_id,
 
   request_info->peer->OnUploadProgress(position, size);
 
-  // Acknowledge receipt
-  message_sender_->Send(new ResourceHostMsg_UploadProgress_ACK(request_id));
+  if (!request_info->url_loader) {
+    // Acknowledge receipt
+    message_sender_->Send(new ResourceHostMsg_UploadProgress_ACK(request_id));
+  }
 }
 
 void ResourceDispatcher::OnReceivedResponse(