Reduce unnecessary download interruptions due to parallel requests

content/browser/download/download_worker.cc

Index: content/browser/download/download_worker.cc
diff --git a/content/browser/download/download_worker.cc b/content/browser/download/download_worker.cc
index 6e330a28f4ef41528d37a64fb7edd8f43fe5f24f..5eff1cf3b38a134ff8f12c54e3f57b06a360abc6 100644
--- a/content/browser/download/download_worker.cc
+++ b/content/browser/download/download_worker.cc
@@ -13,6 +13,23 @@ namespace {
 
 const int kVerboseLevel = 1;
 
+class CompletedByteStreamReader : public ByteStreamReader {
+ public:
+  CompletedByteStreamReader(int status) : status_(status) {};
+  ~CompletedByteStreamReader() override = default;
+
+  // ByteStreamReader implementations:
+  ByteStreamReader::StreamState Read(scoped_refptr<net::IOBuffer>* data,
+                                     size_t* length) override {
+    return ByteStreamReader::STREAM_COMPLETE;
+  }
+  int GetStatus() const override { return status_; }
+  void RegisterCallback(const base::Closure& sink_callback) override {};
+
+ private:
+  int status_;
+};
+
 std::unique_ptr<UrlDownloader, BrowserThread::DeleteOnIOThread>
 CreateUrlDownloader(std::unique_ptr<DownloadUrlParameters> params,
                     base::WeakPtr<UrlDownloader::Delegate> delegate) {
@@ -94,9 +111,7 @@ void DownloadWorker::OnUrlDownloaderStarted(
       DownloadInterruptReason::DOWNLOAD_INTERRUPT_REASON_NONE) {
     VLOG(kVerboseLevel) << "Parallel download sub-request failed. reason = "
                         << create_info->result;
-
-    delegate_->OnServerResponseError(this, create_info->result);
-    return;
+    stream_reader.reset(new CompletedByteStreamReader(create_info->result));
   }
 
   request_handle_ = std::move(create_info->request_handle);