Treat already existing saved pages as success.

chrome/browser/android/offline_pages/prerendering_offliner.cc

Index: chrome/browser/android/offline_pages/prerendering_offliner.cc
diff --git a/chrome/browser/android/offline_pages/prerendering_offliner.cc b/chrome/browser/android/offline_pages/prerendering_offliner.cc
index 899bc1070eb66a479878c82f7a481f5d586dbec4..a8afa1758733595723433b567b3db0b1598fcb65 100644
--- a/chrome/browser/android/offline_pages/prerendering_offliner.cc
+++ b/chrome/browser/android/offline_pages/prerendering_offliner.cc
@@ -157,7 +157,9 @@ void PrerenderingOffliner::OnSavePageDone(
 
   // Determine status and run the completion callback.
   Offliner::RequestStatus save_status;
-  if (save_result == SavePageResult::SUCCESS) {
+  if (save_result == SavePageResult::ALREADY_EXISTS) {
+    save_status = RequestStatus::SAVED;
+  } else if (save_result == SavePageResult::SUCCESS) {
     if (saved_on_last_retry_)
       save_status = RequestStatus::SAVED_ON_LAST_RETRY;
     else