Refactor root element background painting

Source/core/style/FillLayer.cpp

Index: Source/core/style/FillLayer.cpp
diff --git a/Source/core/style/FillLayer.cpp b/Source/core/style/FillLayer.cpp
index 2d1945394befb07e33de9ecff0dc82e8bc091eec..2709ff3e21247d5b2b7c80dc90426c0aa7296b18 100644
--- a/Source/core/style/FillLayer.cpp
+++ b/Source/core/style/FillLayer.cpp
@@ -361,12 +361,15 @@ bool FillLayer::hasOpaqueImage(const LayoutObject* layoutObject) const
     if (!m_image)
         return false;
 
-    if (m_composite == CompositeClear || m_composite == CompositeCopy)
+    if (m_composite == CompositeClear)
         return true;
 
     if (m_blendMode != WebBlendModeNormal)
         return false;
 
+    if (m_composite == CompositeCopy)
+        return true;
+
     if (m_composite == CompositeSourceOver)
         return m_image->knownToBeOpaque(layoutObject);