Added DownloadItem::Observer to JobController.

content/browser/background_fetch/background_fetch_job_data.cc

Index: content/browser/background_fetch/background_fetch_job_data.cc
diff --git a/content/browser/background_fetch/background_fetch_job_data.cc b/content/browser/background_fetch/background_fetch_job_data.cc
index 0d0f30a6ca2d413129ab968ff8547af5b6b9691e..005780c31e05c08a3b7bb04d40bc274e3025a2fe 100644
--- a/content/browser/background_fetch/background_fetch_job_data.cc
+++ b/content/browser/background_fetch/background_fetch_job_data.cc
@@ -54,4 +54,11 @@ bool BackgroundFetchJobData::HasRequestsRemaining() const {
   return next_request_info_ != request_infos_.size();
 }
 
+void BackgroundFetchJobData::SetRequestDownloadGuid(
+    const std::string& request_guid,
+    const std::string& download_guid) {
+  auto index_iter = request_info_index_.find(request_guid);
+  DCHECK(index_iter != request_info_index_.end());
+  request_infos_[index_iter->second].set_download_guid(download_guid);
+}
 }  // namespace content