Basic windowless plugins, try 2.

webkit/glue/plugins/plugin_instance.h

 // Copyright (c) 2006-2008 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.
 
 // TODO: Need to deal with NPAPI's NPSavedData.
 //       I haven't seen plugins use it yet.
 
 #ifndef WEBKIT_GLUE_PLUGIN_PLUGIN_INSTANCE_H__
 #define WEBKIT_GLUE_PLUGIN_PLUGIN_INSTANCE_H__
 
@@ skipping 81 matching lines @@
 
   // Get the mimeType for this plugin stream
   const std::string &mime_type() { return mime_type_; }
 
   NPAPI::PluginLib* plugin_lib() { return plugin_; }
 
 #if defined(OS_WIN)
   // Handles a windows native message which this PluginInstance should deal
   // with.  Returns true if the event is handled, false otherwise.
   bool HandleEvent(UINT message, WPARAM wParam, LPARAM lParam);
+#elif defined(OS_LINUX)
+  bool HandleEvent(union _XEvent* event);
 #endif
 
   // Creates a stream for sending an URL.  If notify_needed
   // is true, it will send a notification to the plugin
   // when the stream is complete; otherwise it will not.
   // Set object_url to true if the load is for the object tag's
   // url, or false if it's for a url that the plugin
   // fetched through NPN_GetUrl[Notify].
   PluginStreamUrl *CreateStream(int resource_id,
                                 const std::string &url,
@@ skipping 140 matching lines @@
   // List of files created for the current plugin instance. File names are
   // added to the list every time the NPP_StreamAsFile function is called.
   std::vector<FilePath> files_created_;
 
   DISALLOW_EVIL_CONSTRUCTORS(PluginInstance);
 };
 
 } // namespace NPAPI
 
 #endif  // WEBKIT_GLUE_PLUGIN_PLUGIN_INSTANCE_H__