Revert of Calculate paint invalidation rect for scrollbars

third_party/WebKit/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 1282 matching lines @@
         return mayNeedPaintInvalidation() || shouldDoFullPaintInvalidation() || shouldInvalidateSelection() || m_bitfields.childShouldCheckForPaintInvalidation();
     }
 
     virtual bool supportsPaintInvalidationStateCachedOffsets() const { return !hasTransformRelatedProperty() && !hasReflection() && !style()->isFlippedBlocksWritingMode(); }
 
     virtual LayoutRect viewRect() const;
 
     DisplayItemClient displayItemClient() const { return toDisplayItemClient(this); }
 
     void invalidateDisplayItemClient(const DisplayItemClientWrapper&) const;
-    void invalidateDisplayItemClientsIncludingNonCompositingDescendants(const LayoutBoxModelObject* paintInvalidationContainer, PaintInvalidationReason, const LayoutRect* paintInvalidationRect) const;
+    void invalidateDisplayItemClientForNonCompositingDescendants() const { invalidateDisplayItemClientForNonCompositingDescendantsOf(*this); }
+    // A normal object should use invalidateDisplayItemClientForNonCompositingDescendants()
+    // to invalidate its descendants which are painted on the same backing. However, for
+    // an object (e.g. LayoutScrollbarPart, custom scroll corner, custom resizer) which is
+    // not hooked up in the layout tree and not able to find its paint backing, it should
+    // let its owning layout object call the following function.
+    // FIXME: should we hook up scrollbar parts in the layout tree? crbug.com/484263.
+    void invalidateDisplayItemClientForNonCompositingDescendantsOf(const LayoutObject&) const;
 
     // Called before anonymousChild.setStyle(). Override to set custom styles for the child.
     virtual void updateAnonymousChildStyle(const LayoutObject& anonymousChild, ComputedStyle& style) const { }
 
     // Painters can use const methods only, except for these explicitly declared methods.
     class MutableForPainting {
     public:
         void setPreviousPaintOffset(const LayoutPoint& paintOffset) { m_layoutObject.setPreviousPaintOffset(paintOffset); }
 
     private:
@@ skipping 726 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