sync: Introduce control data types

chrome/browser/sync/glue/sync_backend_host.h

 // Copyright (c) 2012 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_GLUE_SYNC_BACKEND_HOST_H_
 #define CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 126 matching lines @@
 };
 
 // A UI-thread safe API into the sync backend that "hosts" the top-level
 // syncapi element, the SyncManager, on its own thread. This class handles
 // dispatch of potentially blocking calls to appropriate threads and ensures
 // that the SyncFrontend is only accessed on the UI loop.
 class SyncBackendHost : public BackendDataTypeConfigurer {
  public:
   typedef syncer::SyncStatus Status;
 
+  // A static list of types to be downloaded between SyncManager init and
+  // reporting to the frontend that initialization has completed.
+  static syncer::ModelTypeSet EarlyDownloadTypes();
+
   // Create a SyncBackendHost with a reference to the |frontend| that
   // it serves and communicates to via the SyncFrontend interface (on
   // the same thread it used to call the constructor).  Must outlive
   // |sync_prefs| and |invalidator_storage|.
   SyncBackendHost(
       const std::string& name,
       Profile* profile,
       const base::WeakPtr<SyncPrefs>& sync_prefs,
       // TODO(tim): Temporary, remove when bug 124137 finished.
       const base::WeakPtr<InvalidatorStorage>& invalidator_storage);
@@ skipping 373 matching lines @@
   // it via OnBackendInitialized in the final state of
   // HandleInitializationCompletedOnFrontendLoop.
   syncer::WeakHandle<syncer::JsBackend> js_backend_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncBackendHost);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_H_