[S.P.] Invalidate the document element for view background when needed

Source/core/layout/LayoutObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 239 matching lines @@
 
     void assertSubtreeClearedPaintInvalidationState() const
     {
         for (const LayoutObject* renderer = this; renderer; renderer = renderer->nextInPreOrder())
             renderer->assertRendererClearedPaintInvalidationState();
     }
 
 #endif
 
     // FIXME: This could be used when changing the size of a renderer without children to skip some invalidations.
-    bool rendererHasNoBoxEffect() const
+    // FIXME: This is incorrect for document element. Remove this when we enable slimming paint.
+    bool rendererHasNoBoxEffectObsolete() const
     {
         return !style()->hasVisualOverflowingEffect() && !style()->hasBorder() && !style()->hasBackground();
     }
 
+    // Correct version of !rendererHasNoBoxEffectObsolete().
+    bool hasBoxEffect() const
+    {
+        return hasBoxDecorationBackground() || style()->hasVisualOverflowingEffect();
+    }
+
     // Obtains the nearest enclosing block (including this block) that contributes a first-line style to our inline
     // children.
     virtual LayoutBlock* firstLineBlock() const;
 
     // Called when an object that was floating or positioned becomes a normal flow object
     // again.  We have to make sure the render tree updates as needed to accommodate the new
     // normal flow object.
     void handleDynamicFloatPositionChange();
 
     // LayoutObject tree manipulation
@@ skipping 1379 matching lines @@
 void showTree(const blink::LayoutObject*);
 void showLineTree(const blink::LayoutObject*);
 void showLayoutTree(const blink::LayoutObject* object1);
 // We don't make object2 an optional parameter so that showLayoutTree
 // can be called from gdb easily.
 void showLayoutTree(const blink::LayoutObject* object1, const blink::LayoutObject* object2);
 
 #endif
 
 #endif // LayoutObject_h