Implement the algorithm to test merging and overlap in PaintArtifactCompositor.

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 76 matching lines @@
 #include "core/page/AutoscrollController.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/FocusController.h"
 #include "core/page/FrameTree.h"
 #include "core/page/Page.h"
 #include "core/page/scrolling/RootScrollerUtil.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/page/scrolling/TopDocumentRootScrollerController.h"
 #include "core/paint/FramePainter.h"
 #include "core/paint/PaintLayer.h"
+#include "core/paint/PaintPropertyTreePrinter.h"
 #include "core/paint/PrePaintTreeWalk.h"
 #include "core/plugins/PluginView.h"
 #include "core/style/ComputedStyle.h"
 #include "core/svg/SVGDocumentExtensions.h"
 #include "core/svg/SVGSVGElement.h"
 #include "platform/Histogram.h"
 #include "platform/HostWindow.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/ScriptForbiddenScope.h"
 #include "platform/fonts/FontCache.h"
@@ skipping 4555 matching lines @@
   DCHECK(m_frame->isMainFrame());
   return m_initialViewportSize.width();
 }
 
 int FrameView::initialViewportHeight() const {
   DCHECK(m_frame->isMainFrame());
   return m_initialViewportSize.height();
 }
 
 }  // namespace blink