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

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

Index: third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.cpp
diff --git a/third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.cpp b/third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.cpp
index df6ce336cd67a569ae6ee9b3a8fafd813493c799..a0bd8d53ea64cbb81d0bb883d151810c01d69719 100644
--- a/third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.cpp
+++ b/third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.cpp
@@ -35,11 +35,21 @@ namespace blink {
 
 namespace LayoutTreeBuilderTraversal {
 
+inline static bool hasDisplayContentsStyle(const Node& node) {
+  return node.isElementNode() && toElement(node).displayContentsStyle();
+}
+
 static bool isLayoutObjectReparented(const LayoutObject* layoutObject) {
   if (!layoutObject->node()->isElementNode())
     return false;
+
   if (toElement(layoutObject->node())->isInTopLayer())
     return true;
+
+  if (layoutObject->node()->parentNode() &&
+      hasDisplayContentsStyle(*layoutObject->node()->parentNode()))
+    return true;
+
   return false;
 }
 
@@ -68,6 +78,16 @@ ContainerNode* parent(const Node& node, ParentDetails* details) {
   return FlatTreeTraversal::parent(node, details);
 }
 
+LayoutObject* parentLayoutObject(const Node& node) {
+  ContainerNode* parent = LayoutTreeBuilderTraversal::parent(node);
+
+  while (parent && hasDisplayContentsStyle(*parent)) {
+    parent = LayoutTreeBuilderTraversal::parent(*parent);
+  }
+
+  return parent ? parent->layoutObject() : nullptr;
+}
+
 Node* nextSibling(const Node& node) {
   if (node.isBeforePseudoElement()) {
     assertPseudoElementParent(toPseudoElement(node));