[css-display] Support display: contents pseudo-elements.

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 17 matching lines @@
 
 #include "core/layout/LayoutObject.h"
 
 #include <algorithm>
 #include <memory>
 
 #include "core/animation/ElementAnimations.h"
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/AXObjectCache.h"
 #include "core/dom/ElementTraversal.h"
+#include "core/dom/PseudoElement.h"
 #include "core/dom/StyleChangeReason.h"
 #include "core/dom/StyleEngine.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/FrameSelection.h"
 #include "core/editing/TextAffinity.h"
 #include "core/frame/DeprecatedScheduleStyleRecalcDuringLayout.h"
 #include "core/frame/EventHandlerRegistry.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
@@ skipping 1525 matching lines @@
   if (isImage() || isQuote()) {
     RefPtr<ComputedStyle> style = ComputedStyle::create();
     style->inheritFrom(*pseudoStyle);
     setStyle(std::move(style));
     return;
   }
 
   setStyle(std::move(pseudoStyle));
 }
 
+bool LayoutObject::isPseudoElementGeneratedContentFor(
+    const PseudoElement& pseudo) const {
+  return isAnonymous() && m_node.get() == &pseudo;
+}
+
 void LayoutObject::firstLineStyleDidChange(const ComputedStyle& oldStyle,
                                            const ComputedStyle& newStyle) {
   StyleDifference diff = oldStyle.visualInvalidationDiff(newStyle);
 
   if (diff.needsFullPaintInvalidation() ||
       diff.textDecorationOrColorChanged()) {
     // We need to invalidate all inline boxes in the first line, because they
     // need to be repainted with the new style, e.g. background, font style,
     // etc.
     LayoutBlockFlow* firstLineContainer = nullptr;
@@ skipping 1471 matching lines @@
 
   if (RefPtr<ComputedStyle> style = firstLineStyleForCachedUncachedType(
           Cached, isText() ? parent() : this, m_style.get()))
     return style.get();
 
   return m_style.get();
 }
 
 ComputedStyle* LayoutObject::getCachedPseudoStyle(
     PseudoId pseudo,
     const ComputedStyle* parentStyle) const {

[rune, 2017/03/13 10:29:50]

So, longer term, we'd remove this method as well, getting the pseudo style for
::first-line, ::selection, etc from Element as well?

[emilio, 2017/03/13 13:28:31]

Yes, I think that'd be saner.

+  DCHECK_NE(pseudo, PseudoIdBefore);
+  DCHECK_NE(pseudo, PseudoIdAfter);
+
   if (pseudo < FirstInternalPseudoId && !style()->hasPseudoStyle(pseudo))
     return nullptr;
 
   ComputedStyle* cachedStyle = style()->getCachedPseudoStyle(pseudo);
   if (cachedStyle)
     return cachedStyle;
 
   RefPtr<ComputedStyle> result =
       getUncachedPseudoStyle(PseudoStyleRequest(pseudo), parentStyle);
   if (result)
@@ skipping 514 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