Refactor root element background painting

Source/core/layout/LayoutObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 3155 matching lines @@
 {
     // Only full invalidation reasons are allowed.
     ASSERT(isFullPaintInvalidationReason(reason));
 
     bool isUpgradingDelayedFullToFull = m_bitfields.fullPaintInvalidationReason() == PaintInvalidationDelayedFull && reason != PaintInvalidationDelayedFull;
 
     if (m_bitfields.fullPaintInvalidationReason() == PaintInvalidationNone || isUpgradingDelayedFullToFull) {
         if (reason == PaintInvalidationFull)
             reason = documentLifecycleBasedPaintInvalidationReason(document().lifecycle());
         m_bitfields.setFullPaintInvalidationReason(reason);
-
-        if (RuntimeEnabledFeatures::slimmingPaintEnabled() && isBody()) {
-            // The rootObject paints view's background. We need to invalidate it when
-            // view's background changes because of change of body's style.
-            // FIXME: The condition is broader than needed for simplicity.
-            // Might remove this when fixing crbug.com/475115.
-            if (LayoutObject* rootObject = document().documentElement()->layoutObject())
-                rootObject->setShouldDoFullPaintInvalidation();
-        }
     }
 
     if (!isUpgradingDelayedFullToFull) {
         ASSERT(document().lifecycle().state() != DocumentLifecycle::InPaintInvalidation);
         frame()->page()->animator().scheduleVisualUpdate(); // In case that this is called outside of FrameView::updateLayoutAndStyleForPainting().
         markContainerChainForPaintInvalidation();
     }
 }
 
 void LayoutObject::setMayNeedPaintInvalidation()
@@ skipping 100 matching lines @@
         const blink::LayoutObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
     } else {
         fprintf(stderr, "Cannot showLayoutTree. Root is (nil)\n");
     }
 }
 
 #endif