Propagate server response error and interrupt the download.

content/browser/download/download_worker.h

Index: content/browser/download/download_worker.h
diff --git a/content/browser/download/download_worker.h b/content/browser/download/download_worker.h
index 111927471865d74b2d032f7e1217042bafedf6aa..62573e42496d6de9c88490fa1ac10a4d445900ab 100644
--- a/content/browser/download/download_worker.h
+++ b/content/browser/download/download_worker.h
@@ -31,6 +31,9 @@ class DownloadWorker : public UrlDownloader::Delegate {
     virtual void OnByteStreamReady(
         DownloadWorker* worker,
         std::unique_ptr<ByteStreamReader> stream_reader) = 0;
+    // Called when there is an error caused by the server response.
+    virtual void OnServerResponseError(DownloadWorker* worker,
+                                       DownloadInterruptReason reason) = 0;
   };
 
   DownloadWorker(DownloadWorker::Delegate* delegate,
@@ -61,7 +64,7 @@ class DownloadWorker : public UrlDownloader::Delegate {
       std::unique_ptr<UrlDownloader, BrowserThread::DeleteOnIOThread>
           downloader);
 
-  DownloadWorker::Delegate* delegate_;
+  DownloadWorker::Delegate* const delegate_;
 
   // The starting position of the content for this worker to download.
   int64_t offset_;