[LayoutNG] Paint inlines from the fragment tree

third_party/WebKit/Source/core/paint/BoxPainterBase.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/BoxPainterBase.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/Settings.h"
 #include "core/paint/PaintInfo.h"
 #include "core/style/ComputedStyle.h"
@@ skipping 184 matching lines @@
 
 bool BoxPainterBase::ShouldForceWhiteBackgroundForPrintEconomy(
     const Document& document,
     const ComputedStyle& style) {
   return document.Printing() &&
          style.PrintColorAdjust() == EPrintColorAdjust::kEconomy &&
          (!document.GetSettings() ||
           !document.GetSettings()->GetShouldPrintBackgrounds());
 }
 
+bool BoxPainterBase::CalculateFillLayerOcclusionCulling(
+    FillLayerOcclusionOutputList& reversed_paint_list,
+    const FillLayer& fill_layer,
+    const Document& document,
+    const ComputedStyle& style) {
+  bool is_non_associative = false;
+  for (auto current_layer = &fill_layer; current_layer;
+       current_layer = current_layer->Next()) {
+    reversed_paint_list.push_back(current_layer);
+    // Stop traversal when an opaque layer is encountered.
+    // FIXME : It would be possible for the following occlusion culling test to
+    // be more aggressive on layers with no repeat by testing whether the image
+    // covers the layout rect.  Testing that here would imply duplicating a lot
+    // of calculations that are currently done in
+    // LayoutBoxModelObject::paintFillLayer. A more efficient solution might be
+    // to move the layer recursion into paintFillLayer, or to compute the layer
+    // geometry here and pass it down.
+
+    // TODO(trchen): Need to check compositing mode as well.
+    if (current_layer->BlendMode() != kWebBlendModeNormal)
+      is_non_associative = true;
+
+    // TODO(trchen): A fill layer cannot paint if the calculated tile size is
+    // empty.  This occlusion check can be wrong.
+    if (current_layer->ClipOccludesNextLayers() &&
+        current_layer->ImageOccludesNextLayers(document, style)) {
+      if (current_layer->Clip() == kBorderFillBox)
+        is_non_associative = false;
+      break;
+    }
+  }
+  return is_non_associative;
+}
+
 }  // namespace blink