Alternate way to track first paint

Source/core/rendering/RenderView.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 319 matching lines @@
     // short-circuit on full-paint invalidation.
     LayoutRect dirtyRect = viewRect();
     if (doingFullPaintInvalidation() && !dirtyRect.isEmpty()) {
         const RenderLayerModelObject* paintInvalidationContainer = &paintInvalidationState.paintInvalidationContainer();
         mapRectToPaintInvalidationBacking(paintInvalidationContainer, dirtyRect, &paintInvalidationState);
         invalidatePaintUsingContainer(paintInvalidationContainer, dirtyRect, InvalidationFull);
     }
     RenderBlock::invalidateTreeIfNeeded(paintInvalidationState);
 }
 
-void RenderView::invalidatePaintForRectangle(const LayoutRect& paintInvalidationRect) const
+void RenderView::invalidatePaintForRectangle(const LayoutRect& paintInvalidationRect, InvalidationReason invalidationReason) const
 {
     ASSERT(!paintInvalidationRect.isEmpty());
 
     if (document().printing() || !m_frameView)
         return;
 
     ASSERT(layer()->compositingState() == PaintsIntoOwnBacking || !frame()->ownerRenderer());
 
     if (layer()->compositingState() == PaintsIntoOwnBacking) {
-        setBackingNeedsPaintInvalidationInRect(paintInvalidationRect);
+        setBackingNeedsPaintInvalidationInRect(paintInvalidationRect, invalidationReason);
     } else {
         m_frameView->contentRectangleForPaintInvalidation(pixelSnappedIntRect(paintInvalidationRect));
     }
 }
 
 void RenderView::invalidatePaintForViewAndCompositedLayers()
 {
     setShouldDoFullPaintInvalidation(true);
 
     // The only way we know how to hit these ASSERTS below this point is via the Chromium OS login screen.
@@ skipping 536 matching lines @@
     return viewWidth(IncludeScrollbars) / scale;
 }
 
 double RenderView::layoutViewportHeight() const
 {
     float scale = m_frameView ? m_frameView->frame().pageZoomFactor() : 1;
     return viewHeight(IncludeScrollbars) / scale;
 }
 
 } // namespace blink