Revert of Remove FOUC avoidance from BlockPainter and DeprecatedPaintLayerPainter.

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 317 matching lines @@
 
     DECLARE_TRACE();
 
     void setValueForUser(Element*, const String&);
 
     String textSurroundingNode(Node*, int x, int y, unsigned long maxLength);
 
     void setFocused(bool);
     void setInitialFocus(bool);
 
+    bool ignoreLayoutWithPendingStylesheets(Document*);
+
     void setNetworkStateNotifierTestOnly(bool);
     // Test must call setNetworkStateNotifierTestOnly(true) before calling setNetworkConnectionInfo.
     void setNetworkConnectionInfo(const String&, ExceptionState&);
 
     ClientRect* boundsInViewportSpace(Element*);
 
     unsigned countHitRegions(CanvasRenderingContext*);
 
     bool isInCanvasFontCache(Document*, const String&);
     unsigned canvasFontCacheMaxFonts();
@@ skipping 35 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