[OfflinePages] Improve visiblity/handling of "Loading not started" case

components/offline_pages/core/background/request_coordinator.cc

Index: components/offline_pages/core/background/request_coordinator.cc
diff --git a/components/offline_pages/core/background/request_coordinator.cc b/components/offline_pages/core/background/request_coordinator.cc
index f098edfaf85f348f69e0cda5fd4c0201d09d77da..6b6d4d2811dc0b1ab2f8af118a1cebdc6d568af2 100644
--- a/components/offline_pages/core/background/request_coordinator.cc
+++ b/components/offline_pages/core/background/request_coordinator.cc
@@ -846,7 +846,7 @@ void RequestCoordinator::StartOffliner(
   } else {
     is_busy_ = false;
     DVLOG(0) << "Unable to start LoadAndSave";
-    StopProcessing(Offliner::LOADING_NOT_STARTED);
+    StopProcessing(Offliner::LOADING_NOT_ACCEPTED);
 
     // We need to undo the MarkAttemptStarted that brought us to this
     // method since we didn't success in starting after all.