Paint local attachment backgrounds into composited scrolling contents layer

third_party/WebKit/Source/core/paint/BackgroundImageGeometry.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/BackgroundImageGeometry.h"
 
 #include "core/frame/FrameView.h"
 #include "core/layout/LayoutBox.h"
 #include "core/layout/LayoutBoxModelObject.h"
 #include "core/layout/LayoutView.h"
@@ skipping 234 matching lines @@
 }
 
 void BackgroundImageGeometry::useFixedAttachment(const LayoutPoint& attachmentPoint)
 {
     LayoutPoint alignedPoint = attachmentPoint;
     m_phase.move(std::max(alignedPoint.x() - m_destRect.x(), LayoutUnit()), std::max(alignedPoint.y() - m_destRect.y(), LayoutUnit()));
     setPhase(LayoutPoint(roundedIntPoint(m_phase)));
 }
 
 void BackgroundImageGeometry::calculate(const LayoutBoxModelObject& obj, const LayoutBoxModelObject* paintContainer,
-    const GlobalPaintFlags globalPaintFlags, const FillLayer& fillLayer, const LayoutRect& paintRect)
+    const GlobalPaintFlags globalPaintFlags, const FillLayer& fillLayer, const LayoutRect& paintRect, const bool layerIncludesBorders)
 {
     LayoutUnit left;
     LayoutUnit top;
     LayoutSize positioningAreaSize;
     bool isLayoutView = obj.isLayoutView();
     const LayoutBox* rootBox = nullptr;
     if (isLayoutView) {
         // It is only possible reach here when root element has a box.
         Element* documentElement = obj.document().documentElement();
         DCHECK(documentElement);
@@ skipping 16 matching lines @@
         fixedAttachment = false;
     }
 
     if (!fixedAttachment) {
         setDestRect(paintRect);
 
         LayoutUnit right;
         LayoutUnit bottom;
         // Scroll and Local.
         if (fillLayer.origin() != BorderFillBox) {
-            left = LayoutUnit(positioningBox.borderLeft());
-            right = LayoutUnit(positioningBox.borderRight());
-            top = LayoutUnit(positioningBox.borderTop());
-            bottom = LayoutUnit(positioningBox.borderBottom());
+            if (layerIncludesBorders) {
+                left = LayoutUnit(positioningBox.borderLeft());
+                right = LayoutUnit(positioningBox.borderRight());
+                top = LayoutUnit(positioningBox.borderTop());
+                bottom = LayoutUnit(positioningBox.borderBottom());
+            }
             if (fillLayer.origin() == ContentFillBox) {
                 left += positioningBox.paddingLeft();
                 right += positioningBox.paddingRight();
                 top += positioningBox.paddingTop();
                 bottom += positioningBox.paddingBottom();
             }
         }
 
         if (isLayoutView) {
             // The background of the box generated by the root element covers the entire canvas and will
@@ skipping 109 matching lines @@
         useFixedAttachment(paintRect.location());
 
     // Clip the final output rect to the paint rect
     m_destRect.intersect(paintRect);
 
     // Snap as-yet unsnapped values.
     setDestRect(LayoutRect(pixelSnappedIntRect(m_destRect)));
 }
 
 } // namespace blink