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 e0d9f0b90543fa91ffc6413bf7479015ec59d4ea..082772bd689a629707f37ba803f9c39d253e2166 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.isSlotOrActiveInsertionPoint());
+  // 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);
   }
 }
 
@@ -104,10 +106,19 @@ bool LayoutTreeBuilderForElement::shouldCreateLayoutObject() const {
   LayoutObject* parentLayoutObject = this->parentLayoutObject();
   if (!parentLayoutObject)
     return false;
+
   if (!parentLayoutObject->canHaveChildren())
     return false;
 
-  return m_node->layoutObjectIsNeeded(style());
+  // Make sure we keep track of "display: contents" styles.
+  ComputedStyle& style = this->style();
+  if (!m_node->layoutObjectIsNeeded(style)) {
+    if (style.display() == EDisplay::Contents)
+      m_node->storeDisplayContentsStyle(style);

[rune, 2016/11/01 07:12:23]

It's a surprise that shouldCreateLayoutObject has side-effects.

[emilio, 2016/11/01 15:46:31]

Agreed, moved it out of there. Still, createLayoutObjectIfNeeded doesn't seem
like the appropriate method (or at least name) for the place to store it, so
I'll try to find a more appropriate name for that, or a better place to do it.

+    return false;
+  }
+
+  return true;
 }
 
 ComputedStyle& LayoutTreeBuilderForElement::style() const {
@@ -156,7 +167,11 @@ 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))
+             ->displayContentsStyle());
 
   DCHECK(m_node->textLayoutObjectIsNeeded(style, *m_layoutObjectParent));