Fix the bug that negative outline-offset is covered up by composited

third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 94 matching lines @@
 
 LayoutBoxModelObject::LayoutBoxModelObject(ContainerNode* node)
     : LayoutObject(node) {}
 
 bool LayoutBoxModelObject::usesCompositedScrolling() const {
   return hasOverflowClip() && hasLayer() &&
          layer()->getScrollableArea()->usesCompositedScrolling();
 }
 
 bool LayoutBoxModelObject::hasLocalEquivalentBackground() const {
-  int minBorderWidth = std::min(
-      style()->borderTopWidth(),
-      std::min(
-          style()->borderLeftWidth(),
-          std::min(style()->borderRightWidth(), style()->borderBottomWidth())));
-  bool outlineOverlapsPaddingBox = style()->outlineOffset() < -minBorderWidth;
   bool hasCustomScrollbars = false;
   // TODO(flackr): Detect opaque custom scrollbars which would cover up a
   // border-box background.
   if (PaintLayerScrollableArea* scrollableArea = getScrollableArea()) {
     if ((scrollableArea->horizontalScrollbar() &&
          scrollableArea->horizontalScrollbar()->isCustomScrollbar()) ||
         (scrollableArea->verticalScrollbar() &&
          scrollableArea->verticalScrollbar()->isCustomScrollbar())) {
       hasCustomScrollbars = true;
     }
   }
 
   // TODO(flackr): When we correctly clip the scrolling contents layer we can
   // paint locally equivalent backgrounds into it. https://crbug.com/645957
   if (!style()->hasAutoClip())
     return false;
 
   // TODO(flackr): Remove this when box shadows are still painted correctly when
   // painting into the composited scrolling contents layer.
   // https://crbug.com/646464
   if (style()->boxShadow())
     return false;
 
   const FillLayer* layer = &(style()->backgroundLayers());
   for (; layer; layer = layer->next()) {
     if (layer->attachment() == LocalBackgroundAttachment)
       continue;
 
-    // If the outline draws inside the border, it intends to draw on top of the
-    // scroller's background, however because it is painted into a layer behind
-    // the scrolling contents layer we avoid auto promoting in this case to
-    // avoid obscuring the outline.
-    // TODO(flackr): Outlines should be drawn on top of the scrolling contents
-    // layer so that they cannot be covered up by composited scrolling contents.
-    if (outlineOverlapsPaddingBox)
-      return false;
-
     // Solid color layers with an effective background clip of the padding box
     // can be treated as local.
     if (!layer->image() && !layer->next() &&
         resolveColor(CSSPropertyBackgroundColor).alpha() > 0) {
       EFillBox clip = layer->clip();
       if (clip == PaddingFillBox)
         continue;
       // A border box can be treated as a padding box if the border is opaque or
       // there is no border and we don't have custom scrollbars.
       if (clip == BorderFillBox && !hasCustomScrollbars &&
@@ skipping 1161 matching lines @@
   if (rootElementStyle->hasBackground())
     return false;
 
   if (node() != document().firstBodyElement())
     return false;
 
   return true;
 }
 
 }  // namespace blink