leveldb: Add DBTracker for exposing databases to Chrome's memory-infra.

content/browser/indexed_db/leveldb/leveldb_database.cc

 // Copyright (c) 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.
 
 #include "content/browser/indexed_db/leveldb/leveldb_database.h"
 
 #include <inttypes.h>
 #include <stdint.h>
 
 #include <cerrno>
@@ skipping 123 matching lines @@
   options.write_buffer_size =
       leveldb_env::WriteBufferSize(base::SysInfo::AmountOfTotalDiskSpace(path));
 
   // For info about the troubles we've run into with this parameter, see:
   // https://code.google.com/p/chromium/issues/detail?id=227313#c11
   options.max_open_files = 80;
   options.env = env;
 
   // ChromiumEnv assumes UTF8, converts back to FilePath before using.
   leveldb::DB* db_ptr = nullptr;
-  leveldb::Status s = leveldb::DB::Open(options, path.AsUTF8Unsafe(), &db_ptr);
+  leveldb::Status s = leveldb_env::DBRegistry::Open(options, path.AsUTF8Unsafe(), &db_ptr);
   db->reset(db_ptr);
 
   return s;
 }
 
 leveldb::Status LevelDBDatabase::Destroy(const base::FilePath& file_name) {
   leveldb::Options options;
   options.env = LevelDBEnv::Get();
   // ChromiumEnv assumes UTF8, converts back to FilePath before using.
   return leveldb::DestroyDB(file_name.AsUTF8Unsafe(), options);
@@ skipping 359 matching lines @@
 void LevelDBDatabase::OnIteratorDestroyed(LevelDBIterator* iter) {
   DCHECK_GT(num_iterators_, 0u);
   --num_iterators_;
   auto it = iterator_lru_.Peek(iter);
   if (it == iterator_lru_.end())
     return;
   iterator_lru_.Erase(it);
 }
 
 }  // namespace content