Make DownloadFileImpl handle multiple byte streams.

content/public/test/test_file_error_injector.cc

Index: content/public/test/test_file_error_injector.cc
diff --git a/content/public/test/test_file_error_injector.cc b/content/public/test/test_file_error_injector.cc
index 482720544381d78ca52bc9574a30b847b582c923..0ac3ec6f3a05ad43cbc54aee983975cdcb287842 100644
--- a/content/public/test/test_file_error_injector.cc
+++ b/content/public/test/test_file_error_injector.cc
@@ -111,6 +111,7 @@ DownloadFileWithError::DownloadFileWithError(
                        default_download_directory,
                        std::move(byte_stream),
                        net_log,
+                       false,

[alexmos, 2017/03/02 21:45:14]

nit: consider adding /* is_sparse_file */ for readability, or switching to an
enum

[xingliu, 2017/03/02 23:06:15]

Done.

                        observer),
       error_info_(error_info),
       destruction_callback_(dtor_callback) {