Make it clear what last_sync_timestamp actually tracks. Update

chrome/browser/sync/sessions/sync_session.cc

Index: chrome/browser/sync/sessions/sync_session.cc
diff --git a/chrome/browser/sync/sessions/sync_session.cc b/chrome/browser/sync/sessions/sync_session.cc
index 6453a4cdef4adcc1fe332030d440ddd39cdef0a9..7e04d71bd423cf86b55065d579848e9cb7a1477c 100644
--- a/chrome/browser/sync/sessions/sync_session.cc
+++ b/chrome/browser/sync/sessions/sync_session.cc
@@ -53,12 +53,10 @@ bool SyncSession::HasMoreToSync() const {
   return ((status->commit_ids().size() < status->unsynced_handles().size()) &&
       status->syncer_status().num_successful_commits > 0) ||
       status->conflict_sets_built() ||
-      status->conflicts_resolved() ||
+      status->conflicts_resolved();
       // Or, we have conflicting updates, but we're making progress on
       // resolving them...
-      !status->got_zero_updates() ||
-      status->got_new_timestamp();
-}
+  }
 
 }  // namespace sessions
 }  // namespace browser_sync