Make it clear what last_sync_timestamp actually tracks. Update

chrome/browser/sync/sessions/status_controller.h

 // Copyright (c) 2009 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.
 
 // StatusController handles all counter and status related number crunching and
 // state tracking on behalf of a SyncSession.  It 'controls' the model data
 // defined in session_state.h.  The most important feature of StatusController
 // is the ScopedModelSafetyRestriction. When one of these is active, the
 // underlying data set exposed via accessors is swapped out to the appropriate
 // set for the restricted ModelSafeGroup behind the scenes.  For example, if
@@ skipping 64 matching lines @@
   // ClientToServer messages.
   ClientToServerMessage* mutable_commit_message() {
     return &shared_.commit_message;
   }
   const ClientToServerResponse& commit_response() const {
     return shared_.commit_response;
   }
   ClientToServerResponse* mutable_commit_response() {
     return &shared_.commit_response;
   }
-  const ClientToServerResponse& updates_response() {
+  const ClientToServerResponse& updates_response() const {
     return shared_.updates_response;
   }
   ClientToServerResponse* mutable_updates_response() {
     return &shared_.updates_response;
   }
 
   // Errors and SyncerStatus.
   const ErrorCounters& error_counters() const {
     return shared_.error_counters.value();
   }
@@ skipping 32 matching lines @@
     return shared_.unsynced_handles.value();
   }
 
   // Control parameters for sync cycles.
   bool conflict_sets_built() const {
     return shared_.control_params.conflict_sets_built;
   }
   bool conflicts_resolved() const {
     return shared_.control_params.conflicts_resolved;
   }
-  bool got_new_timestamp() const {
-    return shared_.control_params.got_new_timestamp;
-  }
   bool did_commit_items() const {
     return shared_.control_params.items_committed;
   }
 
   // If a GetUpdates for any data type resulted in downloading an update that
   // is in conflict, this method returns true.
   bool HasConflictingUpdates() const;
 
   // Aggregate sum of ConflictingItemSize() over all ConflictProgress objects
   // (one for each ModelSafeGroup currently in-use).
   int TotalNumConflictingItems() const;
 
   // Returns the number of updates received from the sync server.
   int64 CountUpdates() const;
 
   // Returns true iff any of the commit ids added during this session are
   // bookmark related.
   bool HasBookmarkCommitActivity() const {
     return shared_.commit_set.HasBookmarkCommitId();
   }
 
-  bool got_zero_updates() const { return CountUpdates() == 0; }
+  // Returns true if the last download_updates_command received a valid
+  // server response.
+  bool download_updates_succeeded() const {
+    return updates_response().has_get_updates();
+  }
+
+  // Returns true if the last updates response indicated that we were fully
+  // up to date.  This is subtle: if it's false, it could either mean that
+  // the server said there WAS more to download, or it could mean that we
+  // were unable to reach the server.
+  bool server_says_nothing_more_to_download() const {
+    if (!download_updates_succeeded())
+      return false;
+    // The server indicates "you're up to date" by not sending a new
+    // timestamp.
+    return !updates_response().get_updates().has_new_timestamp();
+  }
 
   ModelSafeGroup group_restriction() const {
     return group_restriction_;
   }
 
   // A toolbelt full of methods for updating counters and flags.
   void increment_num_conflicting_commits_by(int value);
   void reset_num_conflicting_commits();
   void set_num_consecutive_transient_error_commits(int value);
   void increment_num_consecutive_transient_error_commits_by(int value);
   void set_num_consecutive_errors(int value);
   void increment_num_consecutive_errors();
   void increment_num_consecutive_errors_by(int value);
-  void set_got_new_timestamp();
   void set_current_sync_timestamp(syncable::ModelType model,
                                   int64 current_timestamp);
   void set_num_server_changes_remaining(int64 changes_remaining);
   void set_over_quota(bool over_quota);
   void set_invalid_store(bool invalid_store);
   void set_syncer_stuck(bool syncer_stuck);
   void set_syncing(bool syncing);
   void set_num_successful_bookmark_commits(int value);
   void increment_num_successful_commits();
   void increment_num_successful_bookmark_commits();
@@ skipping 59 matching lines @@
   }
  private:
   StatusController* status_;
   DISALLOW_COPY_AND_ASSIGN(ScopedModelSafeGroupRestriction);
 };
 
 }
 }
 
 #endif  // CHROME_BROWSER_SYNC_SESSIONS_STATUS_CONTROLLER_H_