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

chrome/browser/plugins/plugin_finder.cc

 // 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.
 
 #include "chrome/browser/plugins/plugin_finder.h"
 
 #include "base/bind.h"
 #include "base/json/json_reader.h"
 #include "base/message_loop.h"
 #include "base/stl_util.h"
@@ skipping 207 matching lines @@
 }
 
 bool PluginFinder::FindPluginWithIdentifier(
     const std::string& identifier,
     PluginInstaller** installer,
     scoped_ptr<PluginMetadata>* plugin_metadata) {
   base::AutoLock lock(mutex_);
   std::map<std::string, PluginInstaller*>::const_iterator it =
       installers_.find(identifier);
   if (it != installers_.end()) {
-    *installer = it->second;
+    if (installer)
+      *installer = it->second;
     PluginMap::const_iterator metadata_it = identifier_plugin_.find(identifier);
     DCHECK(metadata_it != identifier_plugin_.end());
     *plugin_metadata = metadata_it->second->Clone();
     return true;
   }
 
   return false;
 }
 
 void PluginFinder::ReinitializePlugins(
@@ skipping 58 matching lines @@
       DCHECK(!identifier_plugin_[identifier]);
       identifier_plugin_[identifier] = CreatePluginMetadata(identifier, plugin);
 
 #if defined(ENABLE_PLUGIN_INSTALLATION)
       if (installers_.find(identifier) == installers_.end())
         installers_[identifier] = new PluginInstaller();
 #endif
     }
   }
 }