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, 1 insertions, 13 deletions

diff --git a/sync/sessions/status_controller.h b/sync/sessions/status_controller.h
index eea5872..9844929 100644
--- a/sync/sessions/status_controller.h
+++ b/sync/sessions/status_controller.h
@@ -56,17 +56,11 @@ class SYNC_EXPORT_PRIVATE StatusController {
 
   int num_server_overwrites() const;
 
-  // The time at which we started the first sync cycle in this session.
   base::Time sync_start_time() const {
+    // The time at which we sent the first GetUpdates command for this sync.
     return sync_start_time_;
   }
 
-  // If a poll was performed in this session, the time at which it finished.
-  // Not set if no poll was performed.
-  base::Time poll_finish_time() const {
-    return poll_finish_time_;
-  }
-
   const ModelNeutralState& model_neutral_state() const {
     return model_neutral_;
   }
@@ -97,18 +91,12 @@ class SYNC_EXPORT_PRIVATE StatusController {
   void set_commit_result(const SyncerError result);
 
   void UpdateStartTime();
-  void UpdatePollTime();
 
  private:
   ModelNeutralState model_neutral_;
 
-  // Time the last sync cycle began.
   base::Time sync_start_time_;
 
-  // If a poll was performed, the time it finished. Not set if not poll was
-  // performed.
-  base::Time poll_finish_time_;
-
   DISALLOW_COPY_AND_ASSIGN(StatusController);
 };