Only create sticky position constraints for constrained sticky position.

third_party/WebKit/Source/core/style/ComputedStyle.cpp

 /*
  * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2011 Adobe Systems Incorporated. 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 1179 matching lines @@
   if (TransformStyle3D() == kTransformStyle3DPreserve3D) {
     SetIsStackingContext(true);
     return;
   }
 
   if (is_document_element || is_in_top_layer ||
       StyleType() == kPseudoIdBackdrop || HasOpacity() ||
       HasTransformRelatedProperty() || HasMask() || ClipPath() ||
       BoxReflect() || HasFilterInducingProperty() || HasBackdropFilter() ||
       HasBlendMode() || HasIsolation() || HasViewportConstrainedPosition() ||
+      GetPosition() == EPosition::kSticky ||
       HasPropertyThatCreatesStackingContext(WillChangeProperties()) ||
       ContainsPaint()) {
     SetIsStackingContext(true);
   }
 }
 
 void ComputedStyle::AddCallbackSelector(const String& selector) {
   if (!rare_non_inherited_data_->callback_selectors_.Contains(selector))
     rare_non_inherited_data_.Access()->callback_selectors_.push_back(selector);
 }
@@ skipping 1293 matching lines @@
     if (value < 0)
       fvalue -= 0.5f;
     else
       fvalue += 0.5f;
   }
 
   return RoundForImpreciseConversion<int>(fvalue / zoom_factor);
 }
 
 }  // namespace blink