[Sync] Update SyncBackendHost to forward ClearServerData to SyncManager

chrome/browser/sync/glue/sync_backend_host_core.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_GLUE_SYNC_BACKEND_HOST_CORE_H_
 #define CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_CORE_H_
 
 #include "base/memory/ref_counted.h"
 
 #include "base/timer/timer.h"
@@ skipping 224 matching lines @@
       syncer::ModelTypeSet types,
       scoped_refptr<base::SequencedTaskRunner> task_runner,
       base::Callback<void(const std::vector<syncer::ModelType>& type,
                           ScopedVector<base::ListValue>) > callback);
 
   // Tell the sync manager to persist its state by writing to disk.
   // Called on the sync thread, both by a timer and, on Android, when the
   // application is backgrounded.
   void SaveChanges();
 
+  void DoClearServerData(
+      const syncer::SyncManager::ClearServerDataCallback& frontend_callback);
+
  private:
   friend class base::RefCountedThreadSafe<SyncBackendHostCore>;
   friend class SyncBackendHostForProfileSyncTest;
 
   ~SyncBackendHostCore() override;
 
   // Invoked when initialization of syncapi is complete and we can start
   // our timer.
   // This must be called from the thread on which SaveChanges is intended to
   // be run on; the host's |registrar_->sync_thread()|.
   void StartSavingChanges();
 
+  void ClearServerDataDone(const base::Closure& frontend_callback);
+
   // Name used for debugging.
   const std::string name_;
 
   // Path of the folder that stores the sync data files.
   const base::FilePath sync_data_folder_path_;
 
   // Our parent SyncBackendHost.
   syncer::WeakHandle<SyncBackendHostImpl> host_;
 
   // The loop where all the sync backend operations happen.
@@ skipping 38 matching lines @@
   bool forward_type_info_;
 
   base::WeakPtrFactory<SyncBackendHostCore> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncBackendHostCore);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_CORE_H_