Add update observer to file_system_operation_impl_unittest for

content/public/test/sandbox_file_system_test_helper.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 CONTENT_PUBLIC_TEST_SANDBOX_FILE_SYSTEM_TEST_HELPER_H_
 #define CONTENT_PUBLIC_TEST_SANDBOX_FILE_SYSTEM_TEST_HELPER_H_
 
 #include <string>
 
 #include "base/files/file_path.h"
@@ skipping 59 matching lines @@
 
   // This doesn't work with OFSFU.
   int64 ComputeCurrentOriginUsage();
 
   int64 ComputeCurrentDirectoryDatabaseUsage();
 
   storage::FileSystemOperationRunner* operation_runner();
   storage::FileSystemOperationContext* NewOperationContext();
 
   void AddFileChangeObserver(storage::FileChangeObserver* observer);
+  void AddFileUpdateObserver(storage::FileUpdateObserver* observer);
 
   storage::FileSystemContext* file_system_context() const {
     return file_system_context_.get();
   }
 
   const GURL& origin() const { return origin_; }
   storage::FileSystemType type() const { return type_; }
   storage::StorageType storage_type() const {
     return storage::FileSystemTypeToQuotaStorageType(type_);
   }
   storage::FileSystemFileUtil* file_util() const { return file_util_; }
   storage::FileSystemUsageCache* usage_cache();
 
  private:
   void SetUpFileSystem();
 
   scoped_refptr<storage::FileSystemContext> file_system_context_;
 
   const GURL origin_;
   const storage::FileSystemType type_;
   storage::FileSystemFileUtil* file_util_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_SANDBOX_FILE_SYSTEM_TEST_HELPER_H_