Prevent npapi plugin paint when SkPicture based painting is used.

webkit/plugins/npapi/webplugin_delegate_impl_gtk.cc

 // Copyright (c) 2011 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/plugins/npapi/webplugin_delegate_impl.h"
 
 #include <string>
 #include <vector>
 
 #include <gtk/gtk.h>
@@ skipping 92 matching lines @@
   plugin_->SetWindow(handle);
   return true;
 }
 
 void WebPluginDelegateImpl::PlatformDestroyInstance() {
   // Nothing to do here.
 }
 
 void WebPluginDelegateImpl::Paint(WebKit::WebCanvas* canvas,
                                   const gfx::Rect& rect) {
-  if (!windowless_)
+  if (!windowless_ || !skia::SupportsPlatformPaint(canvas))
     return;
   skia::ScopedPlatformPaint scoped_platform_paint(canvas);
   cairo_t* context = scoped_platform_paint.GetPlatformSurface();
   WindowlessPaint(context, rect);
 }
 
 bool WebPluginDelegateImpl::WindowedCreatePlugin() {
   DCHECK(!windowed_handle_);
   DCHECK(!plug_);
 
@@ skipping 634 matching lines @@
     // as someone might be setting the cursor in the main process as well.
     *cursor = current_windowless_cursor_;
   }
 #endif
 
   return ret;
 }
 
 }  // namespace npapi
 }  // namespace webkit