Add parsing support for display: contents, and minimum behavior similar to display: none

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  *               (http://www.torchmobile.com/)
@@ skipping 170 matching lines @@
       image->setIsGeneratedContent();
     } else {
       image->setImageResource(LayoutImageResource::create());
     }
     image->setStyleInternal(nullptr);
     return image;
   }
 
   switch (style.display()) {
     case EDisplay::None:
+    case EDisplay::Contents:
       return nullptr;
     case EDisplay::Inline:
       return new LayoutInline(element);
     case EDisplay::Block:
     case EDisplay::InlineBlock:
       if (RuntimeEnabledFeatures::layoutNGEnabled())
         return new LayoutNGBlockFlow(element);
       return new LayoutBlockFlow(element);
     case EDisplay::ListItem:
       return new LayoutListItem(element);
@@ skipping 3338 matching lines @@
     const blink::LayoutObject* root = object1;
     while (root->parent())
       root = root->parent();
     root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
   } else {
     WTFLogAlways("%s", "Cannot showLayoutTree. Root is (nil)");
   }
 }
 
 #endif