[Offline Pages] Handle prerender FinalStatus UnsupportedScheme as a cancel rather than failure.

components/offline_pages/background/offliner_policy.h

 // 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.
 
 #ifndef COMPONENTS_OFFLINE_PAGES_BACKGROUND_OFFLINER_POLICY_H_
 #define COMPONENTS_OFFLINE_PAGES_BACKGROUND_OFFLINER_POLICY_H_
 
 namespace {
-const int kMaxStartedTries = 5;
+const int kMaxStartedTries = 3;

[dougarnett, 2016/08/30 20:28:15]

Per dimich request to reduce tries from 5 to 3. On GIN-2g I had a few pages take
3 tries to succesfully load (2 x 2 minutes deadbeat timeouts and then success)
so I would not want to go lower than 3 tries.

[Pete Williamson, 2016/08/30 20:42:47]

This might be better as an unrelated changelist.

[Dmitry Titov, 2016/08/30 23:15:38]

Note 5 or 3 are kinda theoretical w/o actual measurement. I meant that in
general if we use simple heuristics and retry on potentially wide bucket of
outcomes, some of which could be permanent in nature, it makes sense to limit
the number of retries. I don't have specific pref to a particular number.

Do we have enough UMA to see outcomes like "took N retries to load"?

[dougarnett, 2016/08/30 23:27:47]

We don't yet have that UMA and agree we need it. I could add as part of this CL
tomorrow (or as separate CL).

[dougarnett, 2016/08/31 16:10:52]

Per Pete's original request, reverting this change from this CL and will add UMA
in follow-up CL (in which can decide whether to speculatively adjust this
lower). I would like to try some of the EM urls on GIN-2gpoor to help decide
that.

 const int kMaxCompletedTries = 1;
 const int kBackgroundProcessingTimeBudgetSeconds = 170;
 const int kSinglePageTimeLimitSeconds = 120;
 const int kMinimumBatteryPercentageForNonUserRequestOfflining = 50;
 const int kRequestExpirationTimeInSeconds = 60 * 60 * 24 * 7;
 }  // namespace
 
 namespace offline_pages {
 
 // Policy for the Background Offlining system.  Some policy will belong to the
@@ skipping 85 matching lines @@
  private:
   bool prefer_untried_requests_;
   bool prefer_earlier_requests_;
   bool retry_count_is_more_important_than_recency_;
   int max_started_tries_;
   int max_completed_tries_;
 };
 }
 
 #endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_OFFLINER_POLICY_H_