Basic windowless plugins, try 2.

webkit/glue/plugins/plugin_host.cc

 // 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.
 
 // HACK: we need this #define in place before npapi.h is included for
 // plugins to work. However, all sorts of headers include npapi.h, so
 // the only way to be certain the define is in place is to put it
 // here.  You might ask, "Why not set it in npapi.h directly, or in
 // this directory's SConscript, then?"  but it turns out this define
 // makes npapi.h include Xlib.h, which in turn defines a ton of symbols
@@ skipping 759 matching lines @@
 
   case NPNVSupportsXEmbedBool:
     // Yes, we support XEmbed.
     *reinterpret_cast<NPBool*>(value) = TRUE;
     rv = NPERR_NO_ERROR;
     break;
 #endif
   case NPNVSupportsWindowless:
   {
     NPBool* supports_windowless = reinterpret_cast<NPBool*>(value);
-#if defined(OS_LINUX)
-    // TODO(deanm): Remove me once windowless plugins work on Linux.  Right now
-    // it's better to tell the plugin we don't support windowless, then have it
-    // try and fail.
-    *supports_windowless = FALSE;
-#else
     *supports_windowless = TRUE;
-#endif
     rv = NPERR_NO_ERROR;
     break;
   }
   case default_plugin::kMissingPluginStatusStart +
        default_plugin::MISSING_PLUGIN_AVAILABLE:
   // fall through
   case default_plugin::kMissingPluginStatusStart +
        default_plugin::MISSING_PLUGIN_USER_STARTED_DOWNLOAD:
   {
     // This is a hack for the default plugin to send notification to renderer.
@@ skipping 121 matching lines @@
 void NPN_PluginThreadAsyncCall(NPP id,
                          void (*func)(void *),
                          void *userData) {
   scoped_refptr<NPAPI::PluginInstance> plugin = FindInstance(id);
   if (plugin) {
     plugin->PluginThreadAsyncCall(func, userData);
   }
 }
 
 } // extern "C"