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

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

Index: third_party/WebKit/Source/core/dom/Element.cpp
diff --git a/third_party/WebKit/Source/core/dom/Element.cpp b/third_party/WebKit/Source/core/dom/Element.cpp
index 24b75742fc9986422bbe76bbeb7380fefc21829f..1535fd480a6b5d3556f9819f200fd72c0a0972f3 100644
--- a/third_party/WebKit/Source/core/dom/Element.cpp
+++ b/third_party/WebKit/Source/core/dom/Element.cpp
@@ -1527,7 +1527,8 @@ const AtomicString Element::imageSourceURL() const {
 }
 
 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) {
@@ -3133,6 +3134,22 @@ const ComputedStyle* Element::ensureComputedStyle(
   return elementStyle->addCachedPseudoStyle(result.release());
 }
 
+const ComputedStyle* Element::displayContentsStyle() const {
+  if (layoutObject() || !hasRareData())
+    return nullptr;
+
+  ComputedStyle* style = elementRareData()->computedStyle();
+  if (!style || style->display() != EDisplay::Contents)
+    return nullptr;
+
+  return style;
+}
+
+void Element::storeDisplayContentsStyle(ComputedStyle& style) {
+  DCHECK_EQ(style.display(), EDisplay::Contents);
+  ensureElementRareData().setComputedStyle(&style);
+}
+
 AtomicString Element::computeInheritedLanguage() const {
   const Node* n = this;
   AtomicString value;