[SyncFS] Introduce counters in LevelDBWrapper

chrome/browser/sync_file_system/drive_backend/leveldb_wrapper.h

 // Copyright 2014 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_FILE_SYSTEM_DRIVE_BACKEND_LEVELDB_WRAPPER_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_LEVELDB_WRAPPER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 71 matching lines @@
   leveldb::Status Get(const std::string& key, std::string* value);
   scoped_ptr<Iterator> NewIterator();
 
   // Commits pending transactions to |db_| and clears cached transactions.
   // Returns true if the commitment succeeds.
   leveldb::Status Commit();
 
   // Clears pending transactions.
   void Clear();
 
+  // Returns the number of pending PUT/DELETE operations.
+  // Each counter counts operations independently, so operations on a key
+  // may be counted more than once.
+  int64 num_puts() { return num_puts_; }
+  int64 num_deletes() { return num_deletes_; }
+
   // TODO(peria): Rename this method to GetLevelDBForTesting, after removing
   // usages of drive_backend::MigrateDatabaseFromVxToVy() under
   // drive_backend_v1/.
   leveldb::DB* GetLevelDB();
 
  private:
   scoped_ptr<leveldb::DB> db_;
 
   PendingOperationMap pending_;
+  int64 num_puts_;
+  int64 num_deletes_;
 
   DISALLOW_COPY_AND_ASSIGN(LevelDBWrapper);
 };
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_LEVELDB_WRAPPER_H_