storage: Use stl utilities from the base namespace

storage/browser/fileapi/plugin_private_file_system_backend.cc

 // 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.
 
 #include "storage/browser/fileapi/plugin_private_file_system_backend.h"
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
@@ skipping 30 matching lines @@
       NOTREACHED() << "Unsupported url is given: " << url.DebugString();
       return std::string();
     }
     return found->second;
   }
 
   void RegisterFileSystem(const std::string& filesystem_id,
                           const std::string& plugin_id) {
     DCHECK(task_runner_->RunsTasksOnCurrentThread());
     DCHECK(!filesystem_id.empty());
-    DCHECK(!ContainsKey(map_, filesystem_id)) << filesystem_id;
+    DCHECK(!base::ContainsKey(map_, filesystem_id)) << filesystem_id;
     map_[filesystem_id] = plugin_id;
   }
 
   void RemoveFileSystem(const std::string& filesystem_id) {
     DCHECK(task_runner_->RunsTasksOnCurrentThread());
     map_.erase(filesystem_id);
   }
 
  private:
   typedef std::map<std::string, std::string> Map;
@@ skipping 231 matching lines @@
     FileSystemType type) const {
   return NULL;
 }
 
 ObfuscatedFileUtil* PluginPrivateFileSystemBackend::obfuscated_file_util() {
   return static_cast<ObfuscatedFileUtil*>(
       static_cast<AsyncFileUtilAdapter*>(file_util_.get())->sync_file_util());
 }
 
 }  // namespace storage