Ensure that we consistently check contains: paint for fixed position containment.

third_party/WebKit/Source/core/layout/LayoutGeometryMapStep.h

 /*
  * Copyright (C) 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 22 matching lines @@
 #include <memory>
 
 namespace blink {
 
 class LayoutObject;
 
 enum GeometryInfoFlag {
     AccumulatingTransform = 1 << 0,
     IsNonUniform = 1 << 1, // Mapping depends on the input point, e.g. because of CSS columns.
     IsFixedPosition = 1 << 2,
-    HasTransform = 1 << 3,
+    ContainsFixedPosition = 1 << 3,
 };
 typedef unsigned GeometryInfoFlags;
 
 // Stores data about how to map from one layoutObject to its container.
 struct LayoutGeometryMapStep {
     DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
     LayoutGeometryMapStep(const LayoutGeometryMapStep& o)
         : m_layoutObject(o.m_layoutObject)
         , m_offset(o.m_offset)
         , m_offsetForFixedPosition(o.m_offsetForFixedPosition)
@@ skipping 15 matching lines @@
     LayoutSize m_offsetForFixedPosition;
     LayoutSize m_offsetForStickyPosition;
     GeometryInfoFlags m_flags;
 };
 
 } // namespace blink
 
 WTF_ALLOW_MOVE_INIT_AND_COMPARE_WITH_MEM_FUNCTIONS(blink::LayoutGeometryMapStep);
 
 #endif // LayoutGeometryMapStep_h