Force compositing inputs to be clean for getBoundingClientRect

third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 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 86 matching lines @@
     return;
 
   layer()->contentChanged(changeType);
 }
 
 bool LayoutBoxModelObject::hasAcceleratedCompositing() const {
   return view()->compositor()->hasAcceleratedCompositing();
 }
 
 LayoutBoxModelObject::LayoutBoxModelObject(ContainerNode* node)
-    : LayoutObject(node) {}
+    : LayoutObject(node), m_isInStickySubtree(false) {}
 
 bool LayoutBoxModelObject::usesCompositedScrolling() const {
   return hasOverflowClip() && hasLayer() &&
          layer()->getScrollableArea()->usesCompositedScrolling();
 }
 
 BackgroundPaintLocation LayoutBoxModelObject::backgroundPaintLocation() const {
   bool hasCustomScrollbars = false;
   // TODO(flackr): Detect opaque custom scrollbars which would cover up a
   // border-box background.
@@ skipping 296 matching lines @@
       }
     }
 
     if (newStyleIsViewportConstained != oldStyleIsViewportConstrained) {
       if (newStyleIsViewportConstained && layer())
         frameView->addViewportConstrainedObject(this);
       else
         frameView->removeViewportConstrainedObject(this);
     }
   }
+
+  m_isInStickySubtree =
+      style()->position() == StickyPosition ||
+      (parent() && parent()->enclosingBoxModelObject() &&
+       parent()->enclosingBoxModelObject()->isInStickySubtree());
 }
 
 void LayoutBoxModelObject::invalidateStickyConstraints() {
   if (!layer())
     return;
 
   // This intentionally uses the stale ancestor overflow layer compositing input
   // as if we have saved constraints for this layer they were saved in the
   // previous frame.
   DisableCompositingQueryAsserts disabler;
@@ skipping 906 matching lines @@
   if (rootElementStyle->hasBackground())
     return false;
 
   if (node() != document().firstBodyElement())
     return false;
 
   return true;
 }
 
 }  // namespace blink