Change RunAfterStartWorker to not start the worker if it is already running.

content/browser/background_sync/background_sync_manager.cc

Index: content/browser/background_sync/background_sync_manager.cc
diff --git a/content/browser/background_sync/background_sync_manager.cc b/content/browser/background_sync/background_sync_manager.cc
index 926dbca6dc8f72c34b0e91b83f7396a25a86416f..9a8aa4cc9fd29d3b880bb4c6a57ddbfa39bf4f23 100644
--- a/content/browser/background_sync/background_sync_manager.cc
+++ b/content/browser/background_sync/background_sync_manager.cc
@@ -794,9 +794,10 @@ void BackgroundSyncManager::FireOneShotSync(
 
   if (active_version->running_status() != ServiceWorkerVersion::RUNNING) {
     active_version->RunAfterStartWorker(
-        callback, base::Bind(&BackgroundSyncManager::FireOneShotSync,
-                             weak_ptr_factory_.GetWeakPtr(), handle_id,
-                             active_version, last_chance, callback));
+        base::Bind(&BackgroundSyncManager::FireOneShotSync,
+                   weak_ptr_factory_.GetWeakPtr(), handle_id, active_version,
+                   last_chance, callback),
+        callback);
     return;
   }