Adding --disable-plugins-discovery command line switch to not load third-party plugins from common …

content/browser/plugin_service_impl.cc

Index: content/browser/plugin_service_impl.cc
===================================================================
--- content/browser/plugin_service_impl.cc	(revision 204507)
+++ content/browser/plugin_service_impl.cc	(working copy)
@@ -196,6 +196,9 @@
   path = command_line->GetSwitchValuePath(switches::kExtraPluginDir);
   if (!path.empty())
     plugin_list_->AddExtraPluginDir(path);
+
+  if (command_line->HasSwitch(switches::kDisablePluginsDiscovery))
+    plugin_list_->DisablePluginsDiscovery();
 }
 
 void PluginServiceImpl::StartWatchingPlugins() {