Reland of [Background Sync] Allow sync manager access from uncontrolled clients

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 018bbae5ab270ecfc3905a191a9fbb48dd63cb93..6ba38b57924d1e0dbe2ded9e8775ea56e176531d 100644
--- a/content/browser/background_sync/background_sync_manager.cc
+++ b/content/browser/background_sync/background_sync_manager.cc
@@ -73,6 +73,7 @@ BackgroundSyncManager::RegistrationKey::RegistrationKey(
 void BackgroundSyncManager::Register(
     int64 sw_registration_id,
     const BackgroundSyncRegistrationOptions& options,
+    bool requested_from_service_worker,
     const StatusAndRegistrationCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
@@ -93,10 +94,10 @@ void BackgroundSyncManager::Register(
     return;
   }
 
-  op_scheduler_.ScheduleOperation(
-      base::Bind(&BackgroundSyncManager::RegisterImpl,
-                 weak_ptr_factory_.GetWeakPtr(), sw_registration_id, options,
-                 MakeStatusAndRegistrationCompletion(callback)));
+  op_scheduler_.ScheduleOperation(base::Bind(
+      &BackgroundSyncManager::RegisterImpl, weak_ptr_factory_.GetWeakPtr(),
+      sw_registration_id, options, requested_from_service_worker,
+      MakeStatusAndRegistrationCompletion(callback)));
 }
 
 void BackgroundSyncManager::Unregister(
@@ -301,6 +302,7 @@ void BackgroundSyncManager::InitDidGetDataFromBackend(
 void BackgroundSyncManager::RegisterImpl(
     int64 sw_registration_id,
     const BackgroundSyncRegistrationOptions& options,
+    bool requested_from_service_worker,
     const StatusAndRegistrationCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
@@ -335,7 +337,8 @@ void BackgroundSyncManager::RegisterImpl(
     return;
   }
 
-  if (!sw_registration->active_version()->HasWindowClients()) {
+  if (requested_from_service_worker &&
+      !sw_registration->active_version()->HasWindowClients()) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE, base::Bind(callback, BACKGROUND_SYNC_STATUS_NOT_ALLOWED,
                               BackgroundSyncRegistration()));