Keep NaCl plugins used in app background pages alive when active.

chrome/browser/nacl_host/nacl_process_host.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_NACL_HOST_NACL_PROCESS_HOST_H_
 #define CHROME_BROWSER_NACL_HOST_NACL_PROCESS_HOST_H_
 
 #include "build/build_config.h"
 
 #include "base/files/file_path.h"
@@ skipping 212 matching lines @@
 
   bool off_the_record_;
 
   const base::FilePath profile_directory_;
 
   // Channel proxy to terminate the NaCl-Browser PPAPI channel.
   scoped_ptr<IPC::ChannelProxy> ipc_proxy_channel_;
   // Plugin listener, to forward browser channel messages to us.
   PluginListener ipc_plugin_listener_;
   // Browser host for plugin process.
-  scoped_ptr<content::BrowserPpapiHost> ppapi_host_;
+  scoped_refptr<content::BrowserPpapiHost> ppapi_host_;
 
   int render_view_id_;
 
   DISALLOW_COPY_AND_ASSIGN(NaClProcessHost);
 };
 
 #endif  // CHROME_BROWSER_NACL_HOST_NACL_PROCESS_HOST_H_