linux: remove a dcheck that is hit with old plugins

webkit/glue/plugins/webplugin_delegate_impl_gtk.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.
 
 #include "webkit/glue/plugins/webplugin_delegate_impl.h"
 
 #include <string>
 #include <vector>
 
 #include <gtk/gtk.h>
@@ skipping 102 matching lines @@
 }
 
 bool WebPluginDelegateImpl::WindowedCreatePlugin() {
   DCHECK(!windowed_handle_);
   DCHECK(!plug_);
 
   // NPP_GetValue() will write 4 bytes of data to this variable.  Don't use a
   // single byte bool, use an int instead.
   int xembed;
   NPError err = instance_->NPP_GetValue(NPPVpluginNeedsXEmbed, &xembed);
-  DCHECK(err == NPERR_NO_ERROR);
-  if (!xembed) {
-    NOTIMPLEMENTED() << "Windowed plugin but without xembed.";
+  if (err != NPERR_NO_ERROR || !xembed) {
+    NOTIMPLEMENTED() << " windowed plugin but without xembed.";
     return false;
   }
 
   // Passing 0 as the socket XID creates a plug without plugging it in a socket
   // yet, so that it can be latter added with gtk_socket_add_id().
   plug_ = gtk_plug_new(0);
   gtk_widget_show(plug_);
   socket_ = gtk_socket_new();
   gtk_widget_show(socket_);
   gtk_container_add(GTK_CONTAINER(plug_), socket_);
@@ skipping 564 matching lines @@
   if (event->event == WM_MOUSEMOVE) {
     // Snag a reference to the current cursor ASAP in case the plugin modified
     // it. There is a nasty race condition here with the multiprocess browser
     // as someone might be setting the cursor in the main process as well.
     *cursor = current_windowless_cursor_;
   }
 #endif
 
   return ret;
 }