Add retries for completed background loading attempts

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 {
+// The max number of started tries is to guard against pages that make the
+// prerenderer crash.  It should be greater than or equal to the max number of
+// completed tries.
 const int kMaxStartedTries = 4;
-const int kMaxCompletedTries = 1;
+// The number of max completed tries is based on Gin2G-poor testing showing that
+// we often need about 4 retries with a 2 minute window, or 3 retries with a 3

[dougarnett, 2016/11/02 19:28:11]

retries => tries here? 

[Pete Williamson, 2016/11/03 18:34:08]

Done.

+// minute window.
+const int kMaxCompletedTries = 3;
+// By the time we get to a week, the user has forgotten asking for a page.
 const int kRequestExpirationTimeInSeconds = 60 * 60 * 24 * 7;
 
 // Scheduled background processing time limits.
 const int kDozeModeBackgroundServiceWindowSeconds = 60 * 3;
 const int kDefaultBackgroundProcessingTimeBudgetSeconds =
     kDozeModeBackgroundServiceWindowSeconds - 10;
 const int kSinglePageTimeLimitWhenBackgroundScheduledSeconds =
     kDozeModeBackgroundServiceWindowSeconds - 10;
 
 // Immediate processing time limits.
 // Note: experiments on GIN-2g-poor show many page requests took 3 or 4
 // attempts in background scheduled mode with timeout of 2 minutes. So for
 // immediate processing mode, give page requests 4 times that limit (8 min).
 // Then budget up to 5 of those requests in processing window.
 const int kSinglePageTimeLimitForImmediateLoadSeconds = 60 * 8;
 const int kImmediateLoadProcessingTimeBudgetSeconds =
     kSinglePageTimeLimitForImmediateLoadSeconds * 5;
 }  // namespace
 
 namespace offline_pages {
 
 // Policy for the Background Offlining system.  Some policy will belong to the
 // RequestCoordinator, some to the RequestQueue, and some to the Offliner.
 class OfflinerPolicy {
  public:
   OfflinerPolicy()
-      : prefer_untried_requests_(false),
+      : prefer_untried_requests_(true),
         prefer_earlier_requests_(true),
-        retry_count_is_more_important_than_recency_(false),
+        retry_count_is_more_important_than_recency_(true),
         max_started_tries_(kMaxStartedTries),
         max_completed_tries_(kMaxCompletedTries),
         background_scheduled_processing_time_budget_(
             kDefaultBackgroundProcessingTimeBudgetSeconds) {}
 
   // Constructor for unit tests.
   OfflinerPolicy(bool prefer_untried,
                  bool prefer_earlier,
                  bool prefer_retry_count,
                  int max_started_tries,
@@ skipping 85 matching lines @@
   bool prefer_earlier_requests_;
   bool retry_count_is_more_important_than_recency_;
   int max_started_tries_;
   int max_completed_tries_;
   int background_scheduled_processing_time_budget_;
 };
 }  // namespace offline_pages
 
 
 #endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_OFFLINER_POLICY_H_