Support display: contents for elements, first-line and first-letter pseudos.

third_party/WebKit/Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc.
  * All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
@@ skipping 1509 matching lines @@
     return parent->locateNamespacePrefix(namespaceToLocate);
 
   return nullAtom;
 }
 
 const AtomicString Element::imageSourceURL() const {
   return getAttribute(srcAttr);
 }
 
 bool Element::layoutObjectIsNeeded(const ComputedStyle& style) {
-  return style.display() != EDisplay::None;
+  return style.display() != EDisplay::None &&
+         style.display() != EDisplay::Contents;
 }
 
 LayoutObject* Element::createLayoutObject(const ComputedStyle& style) {
   return LayoutObject::createObject(this, style);
 }
 
 Node::InsertionNotificationRequest Element::insertedInto(
     ContainerNode* insertionPoint) {
   // need to do superclass processing first so isConnected() is true
   // by the time we reach updateId
@@ skipping 1585 matching lines @@
 
   RefPtr<ComputedStyle> result =
       document().ensureStyleResolver().pseudoStyleForElement(
           this, PseudoStyleRequest(pseudoElementSpecifier,
                                    PseudoStyleRequest::ForComputedStyle),
           elementStyle);
   DCHECK(result);
   return elementStyle->addCachedPseudoStyle(result.release());
 }
 
+ComputedStyle* Element::displayContentsStyle() const {
+  if (layoutObject() || !hasRareData())
+    return 0;

[jfernandez, 2016/10/27 17:08:01]

return nullptr

+
+  ComputedStyle* style = elementRareData()->computedStyle();
+  if (!style || style->display() != EDisplay::Contents)
+    return 0;

[jfernandez, 2016/10/27 17:08:01]

return nullptr

+
+  return style;
+}
+
+void Element::storeDisplayContentsStyle(ComputedStyle& style) {
+  DCHECK_EQ(style.display(), EDisplay::Contents);
+  ensureElementRareData().setComputedStyle(&style);

[jfernandez, 2016/10/27 17:08:01]

The setComputedStyle argument is a PassRefPtr so I think we would need to ensure
we manage references appropriately. I think we can use std::move to transfer the
reference ownership.  

I think we can also define storeDisplayContentsStyle as Ref<ComputedStyle> as
well.

+}
+
 AtomicString Element::computeInheritedLanguage() const {
   const Node* n = this;
   AtomicString value;
   // The language property is inherited, so we iterate over the parents to find
   // the first language.
   do {
     if (n->isElementNode()) {
       if (const ElementData* elementData = toElement(n)->elementData()) {
         AttributeCollection attributes = elementData->attributes();
         // Spec: xml:lang takes precedence -- http://www.w3.org/TR/xhtml1/#C_7
@@ skipping 948 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(Element) {
   if (hasRareData()) {
     visitor->traceWrappers(elementRareData());
   }
   ContainerNode::traceWrappers(visitor);
 }
 
 }  // namespace blink