Add a FOUC painting test.

Source/platform/graphics/GraphicsLayer.cpp

 /*
  * Copyright (C) 2009 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 442 matching lines @@
 {
     clearContentsLayerIfUnregistered();
     return m_contentsLayer;
 }
 
 void GraphicsLayer::resetTrackedPaintInvalidations()
 {
     paintInvalidationTrackingMap().remove(this);
 }
 
+bool GraphicsLayer::hasTrackedPaintInvalidations() const
+{
+    PaintInvalidationTrackingMap::iterator it = paintInvalidationTrackingMap().find(this);
+    if (it != paintInvalidationTrackingMap().end())
+        return !it->value.invalidationRects.isEmpty();
+    return false;
+}
+
 void GraphicsLayer::trackPaintInvalidationRect(const FloatRect& rect)
 {
     if (rect.isEmpty())
         return;
 
     // The caller must check isTrackingPaintInvalidations() before calling this method
     // to avoid constructing the rect unnecessarily.
     ASSERT(isTrackingPaintInvalidations());
 
     paintInvalidationTrackingMap().add(this, PaintInvalidationTrackingInfo()).storedValue->value.invalidationRects.append(rect);
@@ skipping 683 matching lines @@
 {
     if (!layer) {
         fprintf(stderr, "Cannot showGraphicsLayerTree for (nil).\n");
         return;
     }
 
     String output = layer->layerTreeAsText(blink::LayerTreeIncludesDebugInfo);
     fprintf(stderr, "%s\n", output.utf8().data());
 }
 #endif