Revert of [Sync] Refactoring polling to be reliable. (patchset #5 id:80001 of https://codereview.chromium.org/1132013004/)

Reason for revert:
Failing on valgrind bots

Original issue's description:
> [Sync] Refactoring polling to be reliable.
>
> Polling is now an important component of sync health, as it can sometimes be
> the only time we'll query for certain datatypes. As such, the following
> has changed:
> - Polls that fail will be retried (with backoff).
> - As such, the logic to force a poll after an auth error isn't needed anymore
> - The last successful poll time will be persisted in the sync prefs.
> - On startup, schedule the first poll for last_poll_time + poll_interval
>   (or Now(), whichever is latest).
> - Receiving a new poll interval from the server will update the poll timer
> - The poll timer is now a one shot timer, and only restarts on success
> - Some code cleanup to make the above more straightforward
>
> BUG=482154
>
> Committed: https://crrev.com/3777d8727d7b4caedfb72bfdcbe2fea1f1d1d594
> Cr-Commit-Position: refs/heads/master@{#329669}

TBR=pavely@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=482154

Review URL: https://codereview.chromium.org/1144443004

Cr-Commit-Position: refs/heads/master@{#329683}

1 files changed, 13 insertions, 9 deletions

diff --git a/sync/engine/sync_scheduler_impl.h b/sync/engine/sync_scheduler_impl.h
index b7d8d0b..e3c505b 100644
--- a/sync/engine/sync_scheduler_impl.h
+++ b/sync/engine/sync_scheduler_impl.h
@@ -51,7 +51,7 @@ class SYNC_EXPORT_PRIVATE SyncSchedulerImpl
   // Calls Stop().
   ~SyncSchedulerImpl() override;
 
-  void Start(Mode mode, base::Time last_poll_time) override;
+  void Start(Mode mode) override;
   void ScheduleConfiguration(const ConfigurationParams& params) override;
   void Stop() override;
   void ScheduleLocalNudge(
@@ -151,10 +151,7 @@ class SYNC_EXPORT_PRIVATE SyncSchedulerImpl
   // Invoke the syncer to perform a configuration job.
   void DoConfigurationSyncSessionJob(JobPriority priority);
 
-  // Helper function for Do{Nudge,Configuration,Poll}SyncSessionJob.
-  void HandleSuccess();
-
-  // Helper function for Do{Nudge,Configuration,Poll}SyncSessionJob.
+  // Helper function for Do{Nudge,Configuration}SyncSessionJob.
   void HandleFailure(
       const sessions::ModelNeutralState& model_neutral_state);
 
@@ -249,10 +246,8 @@ class SYNC_EXPORT_PRIVATE SyncSchedulerImpl
   base::TimeDelta syncer_short_poll_interval_seconds_;
   base::TimeDelta syncer_long_poll_interval_seconds_;
 
-  // Timer for polling. Restarted on each successful poll, and when entering
-  // normal sync mode or exiting an error state. Not active in configuration
-  // mode.
-  base::OneShotTimer<SyncSchedulerImpl> poll_timer_;
+  // Periodic timer for polling.  See AdjustPolling.
+  base::RepeatingTimer<SyncSchedulerImpl> poll_timer_;
 
   // The mode of operation.
   Mode mode_;
@@ -296,6 +291,15 @@ class SYNC_EXPORT_PRIVATE SyncSchedulerImpl
   // could result in tight sync loops hitting sync servers.
   bool no_scheduling_allowed_;
 
+  // crbug/251307. This is a workaround for M29. crbug/259913 tracks proper fix
+  // for M30.
+  // The issue is that poll job runs after few hours of inactivity and therefore
+  // will always fail with auth error because of expired access token. Once
+  // fresh access token is requested poll job is not retried.
+  // The change is to remember that poll timer just fired and retry poll job
+  // after credentials are updated.
+  bool do_poll_after_credentials_updated_;
+
   // TryJob might get called for multiple reasons. It should only call
   // DoPollSyncSessionJob after some time since the last attempt.
   // last_poll_reset_ keeps track of when was last attempt.