Sync: Support multiple setup UIs.

ios/chrome/browser/sync/sync_setup_service.h

 // Copyright 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 IOS_CHROME_BROWSER_SYNC_SYNC_SETUP_SERVICE_H_
 #define IOS_CHROME_BROWSER_SYNC_SYNC_SETUP_SERVICE_H_
 
 #include <map>
 
 #include "base/macros.h"
 #include "base/strings/string16.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/util/syncer_error.h"
 
 namespace sync_driver {
 class SyncService;
+class SyncSetupInProgressHandle;
 }
 
 class PrefService;
 
 // Class that allows configuring sync. It handles enabling and disabling it, as
 // well as choosing datatypes. Most actions are delayed until a commit is done,
 // to allow the complex sync setup flow on iOS.
 class SyncSetupService : public KeyedService {
  public:
   typedef enum {
@@ skipping 70 matching lines @@
  private:
   // Enables or disables sync. Changes won't take effect in the sync backend
   // before the next call to |CommitChanges|. No changes are made to the
   // currently selected datatypes.
   void SetSyncEnabledWithoutChangingDatatypes(bool sync_enabled);
 
   sync_driver::SyncService* const sync_service_;
   PrefService* const prefs_;
   syncer::ModelTypeSet user_selectable_types_;
 
+  // Handle preventing Sync from running until configuration is complete.
+  std::unique_ptr<sync_driver::SyncSetupInProgressHandle> setup_handle_;
+
   DISALLOW_COPY_AND_ASSIGN(SyncSetupService);
 };
 
 #endif  // IOS_CHROME_BROWSER_SYNC_SYNC_SETUP_SERVICE_H_