Added AddDownload communication path and observers

content/browser/background_fetch/background_fetch_context.cc

Index: content/browser/background_fetch/background_fetch_context.cc
diff --git a/content/browser/background_fetch/background_fetch_context.cc b/content/browser/background_fetch/background_fetch_context.cc
index 2e087b26459a85969ffd42e8672c0b682521e638..e422bda9613e8656e8129b2989319c894455101d 100644
--- a/content/browser/background_fetch/background_fetch_context.cc
+++ b/content/browser/background_fetch/background_fetch_context.cc
@@ -45,7 +45,8 @@ BackgroundFetchContext::BackgroundFetchContext(
           base::MakeUnique<BackgroundFetchDataManager>(browser_context)),
       event_dispatcher_(base::MakeUnique<BackgroundFetchEventDispatcher>(
           std::move(service_worker_context))),
-      client_proxy_(base::MakeUnique<BackgroundFetchClientProxy>(this)) {
+      client_proxy_(
+          base::MakeUnique<BackgroundFetchClientProxy>(browser_context, this)) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   BackgroundFetchClient* background_fetch_client =
       browser_context_->GetBackgroundFetchClient();
@@ -103,6 +104,11 @@ void BackgroundFetchContext::DidCreateRegistration(
   // Create the BackgroundFetchJobController, which will do the actual fetching.
   CreateController(registration_id, options, std::move(initial_requests));
 
+  // Tell the BackgroundFetchClient that a job has started, which will allow
+  // embedders to display updates.
+  client_proxy_->AddDownload(GURL(registration_id.origin().Serialize()),
+                             registration_id.Serialize(), options);
+
   // Create the BackgroundFetchRegistration the renderer process will receive,
   // which enables it to resolve the promise telling the developer it worked.
   BackgroundFetchRegistration registration;