Merge 121388

Source/WebCore/page/mac/FrameMac.mm

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 139 matching lines @@
 
 NSImage* Frame::snapshotDragImage(Node* node, NSRect* imageRect, NSRect* elementRect) const
 {
     RenderObject* renderer = node->renderer();
     if (!renderer)
         return nil;
     
     renderer->updateDragState(true);    // mark dragged nodes (so they pick up the right CSS)
     m_doc->updateLayout();        // forces style recalc - needed since changing the drag state might
                                         // imply new styles, plus JS could have changed other things
+
+
+    // Document::updateLayout may have blown away the original RenderObject.
+    renderer = node->renderer();
+    if (!renderer)
+        return nil;
+
     LayoutRect topLevelRect;
     NSRect paintingRect = pixelSnappedIntRect(renderer->paintingRootRect(topLevelRect));
 
     m_view->setNodeToDraw(node);              // invoke special sub-tree drawing mode
     NSImage* result = imageFromRect(paintingRect);
     renderer->updateDragState(false);
     m_doc->updateLayout();
     m_view->setNodeToDraw(0);
 
     if (elementRect)
         *elementRect = pixelSnappedIntRect(topLevelRect);
     if (imageRect)
         *imageRect = paintingRect;
     return result;
 }
 
 DragImageRef Frame::nodeImage(Node* node)
 {
+    m_doc->updateLayout(); // forces style recalc
+
     RenderObject* renderer = node->renderer();
     if (!renderer)
         return nil;
-
-    m_doc->updateLayout(); // forces style recalc
-
     LayoutRect topLevelRect;
     NSRect paintingRect = pixelSnappedIntRect(renderer->paintingRootRect(topLevelRect));
 
     m_view->setNodeToDraw(node); // invoke special sub-tree drawing mode
     NSImage* result = imageFromRect(paintingRect);
     m_view->setNodeToDraw(0);
 
     return result;
 }
 
 DragImageRef Frame::dragImageForSelection()
 {
     if (!selection()->isRange())
         return nil;
     return selectionImage();
 }
 
 } // namespace WebCore