Paint solid color and local attachment backgrounds into scrolling layer.

third_party/WebKit/Source/core/paint/PaintLayerPainter.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/PaintLayerPainter.h"
 
 #include "core/frame/FrameView.h"
 #include "core/frame/Settings.h"
 #include "core/layout/LayoutBlock.h"
 #include "core/layout/LayoutView.h"
@@ skipping 17 matching lines @@
 #include "platform/graphics/paint/CompositingRecorder.h"
 #include "platform/graphics/paint/DisplayItemCacheSkipper.h"
 #include "platform/graphics/paint/PaintChunkProperties.h"
 #include "platform/graphics/paint/ScopedPaintChunkProperties.h"
 #include "platform/graphics/paint/SubsequenceRecorder.h"
 #include "platform/graphics/paint/Transform3DDisplayItem.h"
 #include "wtf/Optional.h"
 
 namespace blink {
 
+namespace {
+
 static inline bool shouldSuppressPaintingLayer(const PaintLayer& layer)
 {
     // Avoid painting descendants of the root layer when stylesheets haven't loaded. This avoids some FOUC.
     // It's ok not to draw, because later on, when all the stylesheets do load, Document::styleResolverMayHaveChanged()
     // will invalidate all painted output via a call to LayoutView::invalidatePaintForViewAndCompositedLayers().
     // We also avoid caching subsequences in this mode; see shouldCreateSubsequence().
     if (layer.layoutObject()->document().didLayoutWithPendingStylesheets() && !layer.isRootLayer() && !layer.layoutObject()->isDocumentElement())
         return true;
 
     return false;
 }
 
+} // namespace
+
 void PaintLayerPainter::paint(GraphicsContext& context, const LayoutRect& damageRect, const GlobalPaintFlags globalPaintFlags, PaintLayerFlags paintFlags)
 {
     PaintLayerPaintingInfo paintingInfo(&m_paintLayer, LayoutRect(enclosingIntRect(damageRect)), globalPaintFlags, LayoutSize());
     if (shouldPaintLayerInSoftwareMode(globalPaintFlags, paintFlags))
         paintLayer(context, paintingInfo, paintFlags);
 }
 
 static ShouldRespectOverflowClipType shouldRespectOverflowClip(PaintLayerFlags paintFlags, const LayoutObject* layoutObject)
 {
     return (paintFlags & PaintLayerPaintingOverflowContents || (paintFlags & PaintLayerPaintingChildClippingMaskPhase && layoutObject->hasClipPath())) ? IgnoreOverflowClip : RespectOverflowClip;
@@ skipping 314 matching lines @@
             ASSERT(objectPaintProperties && objectPaintProperties->localBorderBoxProperties());
             PaintChunkProperties properties(context.getPaintController().currentPaintChunkProperties());
             auto& localBorderBoxProperties = *objectPaintProperties->localBorderBoxProperties();
             properties.transform = localBorderBoxProperties.propertyTreeState.transform;
             properties.clip = localBorderBoxProperties.propertyTreeState.clip;
             properties.effect = localBorderBoxProperties.propertyTreeState.effect;
             properties.backfaceHidden = m_paintLayer.layoutObject()->hasHiddenBackface();
             scopedPaintChunkProperties.emplace(context.getPaintController(), m_paintLayer, properties);
         }
 
-        bool shouldPaintBackground = isPaintingCompositedBackground && shouldPaintContent && !selectionOnly;
+        bool paintBackgroundOnForeground = isPaintingScrollingContent && m_paintLayer.shouldPaintBackgroundOntoForeground();
+        bool shouldPaintBackground = shouldPaintContent && !selectionOnly
+            && ((paintBackgroundOnForeground && isPaintingCompositedForeground)
+                || isPaintingCompositedBackground);
         bool shouldPaintNegZOrderList = (isPaintingScrollingContent && isPaintingOverflowContents) || (!isPaintingScrollingContent && isPaintingCompositedBackground);
         bool shouldPaintOwnContents = isPaintingCompositedForeground && shouldPaintContent;
         bool shouldPaintNormalFlowAndPosZOrderLists = isPaintingCompositedForeground;
         bool shouldPaintOverlayScrollbars = isPaintingOverlayScrollbars;
 
         if (shouldPaintBackground) {
             paintBackgroundForFragments(layerFragments, context, paintingInfo.paintDirtyRect,
                 localPaintingInfo, paintFlags);
         }
 
@@ skipping 414 matching lines @@
     if (!m_paintLayer.containsDirtyOverlayScrollbars())
         return;
 
     PaintLayerPaintingInfo paintingInfo(&m_paintLayer, LayoutRect(enclosingIntRect(damageRect)), paintFlags, LayoutSize());
     paintLayer(context, paintingInfo, PaintLayerPaintingOverlayScrollbars);
 
     m_paintLayer.setContainsDirtyOverlayScrollbars(false);
 }
 
 } // namespace blink