Don't call NPP_SetWindow during the painting of windowless plugins....

webkit/glue/plugins/webplugin_delegate_impl.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.
 
 #ifndef WEBKIT_GLUE_PLUGIN_WEBPLUGIN_DELEGATE_IMPL_H_
 #define WEBKIT_GLUE_PLUGIN_WEBPLUGIN_DELEGATE_IMPL_H_
 
 #include "build/build_config.h"
 
 #include <string>
@@ skipping 144 matching lines @@
   // Closes down and destroys our plugin instance.
   void DestroyInstance();
 
 #if !defined(OS_MACOSX)
   // used for windowed plugins
   gfx::PluginWindowHandle windowed_handle_;
   bool windowed_did_set_window_;
   gfx::Rect windowed_last_pos_;
 #endif
 
+  // TODO(dglazkov): No longer used by Windows, make sure the removal
+  // causes no regressions and eliminate from other platforms.
   // this is an optimization to avoid calling SetWindow to the plugin
   // when it is not necessary.  Initially, we need to call SetWindow,
   // and after that we only need to call it when the geometry changes.
   // use this flag to indicate whether we really need it or not.
   bool windowless_needs_set_window_;
 
   // used by windowed and windowless plugins
   bool windowless_;
 
   WebPlugin* plugin_;
@@ skipping 111 matching lines @@
 
   // Holds the current cursor set by the windowless plugin.
   WebCursor current_windowless_cursor_;
 
   friend class WebPluginDelegate;
 
   DISALLOW_EVIL_CONSTRUCTORS(WebPluginDelegateImpl);
 };
 
 #endif  // #ifndef WEBKIT_GLUE_PLUGIN_WEBPLUGIN_DELEGATE_IMPL_H_