[Sync] Convert sync to a static library.

components/sync/syncable/on_disk_directory_backing_store.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 COMPONENTS_SYNC_SYNCABLE_ON_DISK_DIRECTORY_BACKING_STORE_H_
 #define COMPONENTS_SYNC_SYNCABLE_ON_DISK_DIRECTORY_BACKING_STORE_H_
 
 #include <string>
 
 #include "base/files/file_path.h"
 #include "base/macros.h"
-#include "components/sync/base/sync_export.h"
 #include "components/sync/syncable/directory_backing_store.h"
 
 namespace syncer {
 namespace syncable {
 
 // This is the concrete class that provides a useful implementation of
 // DirectoryBackingStore.
-class SYNC_EXPORT OnDiskDirectoryBackingStore : public DirectoryBackingStore {
+class OnDiskDirectoryBackingStore : public DirectoryBackingStore {
  public:
   OnDiskDirectoryBackingStore(const std::string& dir_name,
                               const base::FilePath& backing_file_path);
   ~OnDiskDirectoryBackingStore() override;
   DirOpenResult Load(Directory::MetahandlesMap* handles_map,
                      JournalIndex* delete_journals,
                      MetahandleSet* metahandles_to_purge,
                      Directory::KernelLoadInfo* kernel_load_info) override;
 
  protected:
@@ skipping 14 matching lines @@
   // The path to the sync DB.
   const base::FilePath backing_file_path_;
 
   DISALLOW_COPY_AND_ASSIGN(OnDiskDirectoryBackingStore);
 };
 
 }  // namespace syncable
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_SYNCABLE_ON_DISK_DIRECTORY_BACKING_STORE_H_