sync: use progress markers instead of timestamps during GetUpdates

chrome/browser/sync/engine/syncapi.h

 // Copyright (c) 2010 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.
 
 // This file defines the "sync API", an interface to the syncer
 // backend that exposes (1) the core functionality of maintaining a consistent
 // local snapshot of a hierarchical object set; (2) a means to transactionally
 // access and modify those objects; (3) a means to control client/server
 // synchronization tasks, namely: pushing local object modifications to a
 // server, pulling nonlocal object modifications from a server to this client,
@@ skipping 630 matching lines @@
       OFFLINE_UNSYNCED,
       // Connected and syncing.
       SYNCING,
       // Connected, no pending changes.
       READY,
       // Internal sync error.
       CONFLICT,
       // Can't connect to server, and we haven't completed the initial
       // sync yet.  So there's nothing we can do but wait for the server.
       OFFLINE_UNUSABLE,
+
+      SUMMARY_STATUS_COUNT,
     };
+
     Summary summary;
-
-    // Various server related information.
     bool authenticated;      // Successfully authenticated via GAIA.
     bool server_up;          // True if we have received at least one good
                              // reply from the server.
     bool server_reachable;   // True if we received any reply from the server.
     bool server_broken;      // True of the syncer is stopped because of server
                              // issues.
+    bool notifications_enabled;  // True only if subscribed for notifications.
 
-    bool notifications_enabled;  // True only if subscribed for notifications.
+    // Notifications counters updated by the actions in synapi.
     int notifications_received;
     int notifications_sent;
 
-    // Various Syncer data.
+    // The max number of consecutive errors from any component.
+    int max_consecutive_errors;
+
     int unsynced_count;
+
     int conflicting_count;
     bool syncing;
+    // True after a client has done a first sync.
     bool initial_sync_ended;
+    // True if any syncer is stuck.
     bool syncer_stuck;
+
+    // Total updates available.  If zero, nothing left to download.
     int64 updates_available;
-    int64 updates_received;
+    // Total updates received by the syncer since browser start.
+    int updates_received;
+
+    // Of updates_received, how many were tombstones.
+    int tombstone_updates_received;
     bool disk_full;
-    bool invalid_store;
-    int max_consecutive_errors;  // The max number of errors from any component.
   };
 
   // An interface the embedding application implements to receive notifications
   // from the SyncManager.  Register an observer via SyncManager::AddObserver.
   // This observer is an event driven model as the events may be raised from
   // different internal threads, and simply providing an "OnStatusChanged" type
   // notification complicates things such as trying to determine "what changed",
   // if different members of the Status object are modified from different
   // threads.  This way, the event is explicit, and it is safe for the Observer
   // to dispatch to a native thread or synchronize accordingly.
@@ skipping 301 matching lines @@
   // This allows actual HttpPostProvider subclass implementations to be
   // reference counted, which is useful if a particular implementation uses
   // multiple threads to serve network requests.
   virtual void Destroy(HttpPostProviderInterface* http) = 0;
   virtual ~HttpPostProviderFactory() { }
 };
 
 }  // namespace sync_api
 
 #endif  // CHROME_BROWSER_SYNC_ENGINE_SYNCAPI_H_