[SyncFS] Run ConflictResolver only when it is needed.

chrome/browser/sync_file_system/drive_backend/sync_engine.h

 // Copyright 2013 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.
 
 #ifndef CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
@@ skipping 127 matching lines @@
                    const SyncStatusCallback& callback);
 
   void DidInitialize(SyncEngineInitializer* initializer,
                      SyncStatusCode status);
   void DidProcessRemoteChange(RemoteToLocalSyncer* syncer,
                               const SyncFileCallback& callback,
                               SyncStatusCode status);
   void DidApplyLocalChange(LocalToRemoteSyncer* syncer,
                            const SyncStatusCallback& callback,
                            SyncStatusCode status);
-  void DidFetchChangeList(SyncStatusCallback& callback);
 
   void MaybeStartFetchChanges();
+  void DidResolveConflict(SyncStatusCode status);
+  void DidFetchChanges(SyncStatusCode status);
+
   void UpdateServiceStateFromSyncStatusCode(SyncStatusCode state,
                                             bool used_network);
   void UpdateServiceState(RemoteServiceState state,
                           const std::string& description);
   void UpdateRegisteredApps();
 
   base::FilePath base_dir_;
   base::FilePath temporary_file_dir_;
 
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
 
   scoped_ptr<drive::DriveServiceInterface> drive_service_;
   scoped_ptr<drive::DriveUploaderInterface> drive_uploader_;
   scoped_ptr<MetadataDatabase> metadata_database_;
 
   // These external services are not owned by SyncEngine.
   // The owner of the SyncEngine is responsible for their lifetime.
   // I.e. the owner should declare the dependency explicitly by calling
   // BrowserContextKeyedService::DependsOn().
   drive::DriveNotificationManager* notification_manager_;
   ExtensionServiceInterface* extension_service_;
 
   ObserverList<SyncServiceObserver> service_observers_;
   ObserverList<FileStatusObserver> file_status_observers_;
   RemoteChangeProcessor* remote_change_processor_;
 
   RemoteServiceState service_state_;
 
+  bool should_check_conflict_;
   bool should_check_remote_change_;
   base::TimeTicks time_to_check_changes_;
 
   bool sync_enabled_;
   ConflictResolutionPolicy conflict_resolution_policy_;
   bool network_available_;
 
   scoped_ptr<SyncTaskManager> task_manager_;
 
   base::WeakPtrFactory<SyncEngine> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncEngine);
 };
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_H_