Add a FOUC painting test.

Source/platform/graphics/GraphicsLayer.h

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. 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 202 matching lines @@
     PassRefPtr<JSONObject> layerTreeAsJSON(LayerTreeFlags, RenderingContextMap&) const;
 
     int paintCount() const { return m_paintCount; }
 
     // Return a string with a human readable form of the layer tree, If debug is true
     // pointers for the layers and timing data will be included in the returned string.
     String layerTreeAsText(LayerTreeFlags = LayerTreeNormal) const;
 
     bool isTrackingPaintInvalidations() const { return m_client->isTrackingPaintInvalidations(); }
     void resetTrackedPaintInvalidations();
+    bool hasTrackedPaintInvalidations() const;
     void trackPaintInvalidationRect(const FloatRect&);
     void trackPaintInvalidationObject(const String&);
 
     void addLinkHighlight(LinkHighlight*);
     void removeLinkHighlight(LinkHighlight*);
     // Exposed for tests
     unsigned numLinkHighlights() { return m_linkHighlights.size(); }
     LinkHighlight* linkHighlight(int i) { return m_linkHighlights[i]; }
 
     void setScrollableArea(ScrollableArea*, bool isViewport);
@@ skipping 12 matching lines @@
     void notifyAnimationFinished(double monotonicTime, int group) override;
 
     // WebLayerScrollClient implementation.
     void didScroll() override;
 
     DisplayItemList* displayItemList() override;
 
     // Exposed for tests.
     virtual WebLayer* contentsLayer() const { return m_contentsLayer; }
 
+    ContentLayerDelegate* contentLayerDelegateForTesting() const { return m_contentLayerDelegate.get(); }
+
 #ifndef NDEBUG
     DisplayItemClient displayItemClient() const { return toDisplayItemClient(this); }
     String debugName() const { return m_client->debugName(this) + " debug red fill"; }
 #endif
 
 protected:
     String debugName(WebLayer*) const;
 
     explicit GraphicsLayer(GraphicsLayerClient*);
     // GraphicsLayerFactoryChromium that wants to create a GraphicsLayer need to be friends.
@@ skipping 96 matching lines @@
 };
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the blink namespace for ease of invocation from gdb.
 void PLATFORM_EXPORT showGraphicsLayerTree(const blink::GraphicsLayer*);
 #endif
 
 #endif // GraphicsLayer_h