Block NPAPI plug-ins in Metro mode instead of not loading them at all.

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 "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/web_contents_observer.h"
@@ skipping 43 matching lines @@
                                    const std::string& identifier);
   void OnBlockedOutdatedPlugin(int placeholder_id,
                                const std::string& identifier);
 #if defined(ENABLE_PLUGIN_INSTALLATION)
   void OnFindMissingPlugin(int placeholder_id, const std::string& mime_type);
 
   void OnRemovePluginPlaceholderHost(int placeholder_id);
 #endif
   void OnOpenAboutPlugins();
   void OnCouldNotLoadPlugin(const FilePath& plugin_path);
+  void OnNPAPINotSupported(const std::string& identifier);
 
   base::WeakPtrFactory<PluginObserver> weak_ptr_factory_;
 
 #if defined(ENABLE_PLUGIN_INSTALLATION)
   // Stores all PluginPlaceholderHosts, keyed by their routing ID.
   std::map<int, PluginPlaceholderHost*> plugin_placeholders_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(PluginObserver);
 };
 
 #endif  // CHROME_BROWSER_PLUGINS_PLUGIN_OBSERVER_H_