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

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

Index: third_party/WebKit/Source/core/dom/LayoutTreeBuilder.cpp
diff --git a/third_party/WebKit/Source/core/dom/LayoutTreeBuilder.cpp b/third_party/WebKit/Source/core/dom/LayoutTreeBuilder.cpp
index 8bc3bdc8608255a72cc05e0d33e17b4f0937dd6c..d6df798b0f74e0a0ac49c3206c4ce4bbbb770dde 100644
--- a/third_party/WebKit/Source/core/dom/LayoutTreeBuilder.cpp
+++ b/third_party/WebKit/Source/core/dom/LayoutTreeBuilder.cpp
@@ -49,13 +49,15 @@ LayoutTreeBuilderForElement::LayoutTreeBuilderForElement(Element& element,
                                                          ComputedStyle* style)
     : LayoutTreeBuilder(element, nullptr), m_style(style) {
   DCHECK(!element.isActiveSlotOrActiveInsertionPoint());
+  // TODO(ecobos): Move the first-letter logic inside parentLayoutObject too?
+  // It's an extra (unnecessary) check for text nodes, though.
   if (element.isFirstLetterPseudoElement()) {
     if (LayoutObject* nextLayoutObject =
             FirstLetterPseudoElement::firstLetterTextLayoutObject(element))
       m_layoutObjectParent = nextLayoutObject->parent();
-  } else if (ContainerNode* containerNode =
-                 LayoutTreeBuilderTraversal::parent(element)) {
-    m_layoutObjectParent = containerNode->layoutObject();
+  } else {
+    m_layoutObjectParent =
+        LayoutTreeBuilderTraversal::parentLayoutObject(element);
   }
 }
 
@@ -94,7 +96,6 @@ bool LayoutTreeBuilderForElement::shouldCreateLayoutObject() const {
     return false;
   if (!parentLayoutObject->canHaveChildren())
     return false;
-
   return m_node->layoutObjectIsNeeded(style());
 }
 
@@ -144,7 +145,11 @@ void LayoutTreeBuilderForElement::createLayoutObject() {
 }
 
 void LayoutTreeBuilderForText::createLayoutObject() {
-  ComputedStyle& style = m_layoutObjectParent->mutableStyleRef();
+  ComputedStyle& style = *m_style;
+
+  DCHECK(m_style == m_layoutObjectParent->style() ||
+         toElement(LayoutTreeBuilderTraversal::parent(*m_node))
+             ->hasDisplayContentsStyle());
 
   DCHECK(m_node->textLayoutObjectIsNeeded(style, *m_layoutObjectParent));