Treat already existing saved pages as success.

chrome/browser/android/offline_pages/background_loader_offliner.cc

Index: chrome/browser/android/offline_pages/background_loader_offliner.cc
diff --git a/chrome/browser/android/offline_pages/background_loader_offliner.cc b/chrome/browser/android/offline_pages/background_loader_offliner.cc
index 3ff7ad6e177676c6b2319a9e80513ae8ad16b41f..15a47cf8d910923128aa6ed85fd4e14c85b1dc97 100644
--- a/chrome/browser/android/offline_pages/background_loader_offliner.cc
+++ b/chrome/browser/android/offline_pages/background_loader_offliner.cc
@@ -364,7 +364,8 @@ void BackgroundLoaderOffliner::OnPageSaved(SavePageResult save_result,
   save_state_ = NONE;
 
   Offliner::RequestStatus save_status;
-  if (save_result == SavePageResult::SUCCESS) {
+  if (save_result == SavePageResult::SUCCESS ||
+      save_result == SavePageResult::ALREADY_EXISTS) {

[fgorski, 2017/04/24 19:51:51]

Hey, 3 questions:
1. Did you check if we maybe remove the file if we get already_exists.

2. Also if it already exists, why would you consider it "on last retry" below?

3. What about a corresponding change on Prerendering offliner side to keep the
expectation in line?

[Pete Williamson, 2017/04/25 00:09:00]

We don't remove it, because we then get the same error on the next try.
It's a bit ambiguous, but I changed the code to not count it as a last retry.
Done (but no unit test added).

     if (did_snapshot_on_last_retry)
       save_status = RequestStatus::SAVED_ON_LAST_RETRY;
     else