Treat already existing saved pages as success.

chrome/browser/android/offline_pages/prerendering_offliner.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/android/offline_pages/prerendering_offliner.h"
 
 #include "base/bind.h"
 #include "base/json/json_writer.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/sys_info.h"
@@ skipping 139 matching lines @@
   }
 
   // Clear pending request and app listener here and then inform loader we
   // are done with WebContents.
   pending_request_.reset(nullptr);
   app_listener_.reset(nullptr);
   GetOrCreateLoader()->StopLoading();
 
   // 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
       save_status = RequestStatus::SAVED;
   } else {
     // TODO(dougarnett): Consider reflecting some recommendation to retry the
     // request based on specific save error cases.
     save_status = RequestStatus::SAVE_FAILED;
   }
   saved_on_last_retry_ = false;
@@ skipping 158 matching lines @@
 void PrerenderingOffliner::HandleApplicationStateChangeCancel(
     const SavePageRequest& request,
     int64_t offline_id) {
   // This shouldn't be immediate, but account for case where request was reset
   // while waiting for callback.
   if (pending_request_ && pending_request_->request_id() != offline_id)
     return;
   completion_callback_.Run(request, RequestStatus::FOREGROUND_CANCELED);
 }
 }  // namespace offline_pages