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

third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp

Index: third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp b/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
index 4e1053ee3d1a7108222689c7fb45bb0ec4c51d73..9157dd486f8593b8e2245f5d97f48b65bb54f024 100644
--- a/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
+++ b/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
@@ -339,8 +339,11 @@ void GraphicsLayer::notifyFirstPaintToClient() {
     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;