Remove stl_util's deletion function use from chrome/.

chrome/browser/plugins/plugin_observer.h

 // Copyright (c) 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 CHROME_BROWSER_PLUGINS_PLUGIN_OBSERVER_H_
 #define CHROME_BROWSER_PLUGINS_PLUGIN_OBSERVER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 53 matching lines @@
 #if BUILDFLAG(ENABLE_PLUGIN_INSTALLATION)
   void OnRemovePluginPlaceholderHost(int placeholder_id);
 #endif
   void RemoveComponentObserver(int placeholder_id);
   void OnOpenAboutPlugins();
   void OnShowFlashPermissionBubble();
   void OnCouldNotLoadPlugin(const base::FilePath& plugin_path);
 
 #if BUILDFLAG(ENABLE_PLUGIN_INSTALLATION)
   // Stores all PluginPlaceholderHosts, keyed by their routing ID.
-  std::map<int, PluginPlaceholderHost*> plugin_placeholders_;
+  std::map<int, std::unique_ptr<PluginPlaceholderHost>> plugin_placeholders_;
 #endif
 
   // Stores all ComponentObservers, keyed by their routing ID.
   std::map<int, std::unique_ptr<ComponentObserver>> component_observers_;
 
   base::WeakPtrFactory<PluginObserver> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginObserver);
 };
 
 #endif  // CHROME_BROWSER_PLUGINS_PLUGIN_OBSERVER_H_