Basic windowless plugins, try 2.

webkit/glue/plugins/webplugin_delegate_impl.h

Index: webkit/glue/plugins/webplugin_delegate_impl.h
diff --git a/webkit/glue/plugins/webplugin_delegate_impl.h b/webkit/glue/plugins/webplugin_delegate_impl.h
index 27e17cf0f1ec70f6f197d0368b654e0075d9561d..c45b8f3b2a581e0bb4b3e8d02be89b463c1ca34b 100644
--- a/webkit/glue/plugins/webplugin_delegate_impl.h
+++ b/webkit/glue/plugins/webplugin_delegate_impl.h
@@ -19,6 +19,10 @@
 #include "webkit/glue/webplugin_delegate.h"
 #include "webkit/glue/webcursor.h"
 
+#if defined(OS_LINUX)
+typedef struct _GdkDrawable GdkPixmap;
+#endif
+
 namespace NPAPI {
   class PluginInstance;
 };
@@ -177,6 +181,14 @@ class WebPluginDelegateImpl : public WebPluginDelegate {
   bool is_calling_wndproc;
 #endif // OS_WIN
 
+#if defined(OS_LINUX)
+  // The pixmap we're drawing into, for a windowless plugin.
+  GdkPixmap* pixmap_;
+
+  // Ensure pixmap_ exists and is at least width by height pixels.
+  void EnsurePixmapAtLeastSize(int width, int height);
+#endif
+
   gfx::NativeView parent_;
   NPWindow window_;
 #if defined(OS_MACOSX)