Avoid touching z-index in StyleAdjuster by using an isStackingContext flag instead

third_party/WebKit/Source/core/testing/Internals.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple 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.
@@ skipping 216 matching lines @@
     InternalRuntimeFlags* runtimeFlags() const;
     unsigned workerThreadCount() const;
 
     void setDeviceProximity(Document*, const String& eventType, double value, double min, double max, ExceptionState&);
 
     String layerTreeAsText(Document*, unsigned flags, ExceptionState&) const;
     String layerTreeAsText(Document*, ExceptionState&) const;
     String elementLayerTreeAsText(Element*, unsigned flags, ExceptionState&) const;
     String elementLayerTreeAsText(Element*, ExceptionState&) const;
 
+    bool isStackingContext(Element*) const;
+
     bool scrollsWithRespectTo(Element*, Element*, ExceptionState&);
 
     String scrollingStateTreeAsText(Document*) const;
     String mainThreadScrollingReasons(Document*, ExceptionState&) const;
     ClientRectList* nonFastScrollableRects(Document*, ExceptionState&) const;
 
     void evictAllResources() const;
 
     unsigned numberOfLiveNodes() const;
     unsigned numberOfLiveDocuments() const;
@@ skipping 164 matching lines @@
 
     DocumentMarker* markerAt(Node*, const String& markerType, unsigned index, ExceptionState&);
     Member<InternalRuntimeFlags> m_runtimeFlags;
 
     IterationSource* startIteration(ScriptState*, ExceptionState&) override;
 };
 
 } // namespace blink
 
 #endif // Internals_h