Update First Paint to include paint of non-default document background color

third_party/WebKit/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 321 matching lines @@
   notifyFirstPaintToClient();
   return true;
 }
 
 void GraphicsLayer::notifyFirstPaintToClient() {
   bool isFirstPaint = false;
   if (!m_painted) {
     DisplayItemList& itemList = m_paintController->newDisplayItemList();
     for (DisplayItem& item : itemList) {
       DisplayItem::Type type = item.getType();
+      if (type == DisplayItem::kDocumentBackground &&
+          !m_paintController->nonDefaultBackgroundColorPainted()) {
+        continue;
+      }
       if (DisplayItem::isDrawingType(type) &&
-          type != DisplayItem::kDocumentBackground &&
           static_cast<const DrawingDisplayItem&>(item).picture()) {
         m_painted = true;
         isFirstPaint = true;
         break;
       }
     }
   }
   m_client->notifyPaint(isFirstPaint, m_paintController->textPainted(),
                         m_paintController->imagePainted());
 }
@@ skipping 951 matching lines @@
 void showGraphicsLayerTree(const blink::GraphicsLayer* layer) {
   if (!layer) {
     fprintf(stderr, "Cannot showGraphicsLayerTree for (nil).\n");
     return;
   }
 
   String output = layer->layerTreeAsText(blink::LayerTreeIncludesDebugInfo);
   fprintf(stderr, "%s\n", output.utf8().data());
 }
 #endif