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..45cd8ea622ac4127f4892793419113a70e659a7e 100644
--- a/third_party/WebKit/Source/core/dom/LayoutTreeBuilder.cpp
+++ b/third_party/WebKit/Source/core/dom/LayoutTreeBuilder.cpp
@@ -49,13 +49,14 @@ LayoutTreeBuilderForElement::LayoutTreeBuilderForElement(Element& element,
                                                          ComputedStyle* style)
     : LayoutTreeBuilder(element, nullptr), m_style(style) {
   DCHECK(!element.isSlotOrActiveInsertionPoint());
+  // FIXME: Move the first-letter logic inside parentLayoutObject too?

[jfernandez, 2016/10/27 17:08:02]

We use to define this kind of comments with TODO (name) instead of fixme, so we
can know who to ask for clarifications, if necessary.

   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 +105,19 @@ bool LayoutTreeBuilderForElement::shouldCreateLayoutObject() const {
   LayoutObject* parentLayoutObject = this->parentLayoutObject();
   if (!parentLayoutObject)
     return false;
+

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

Remove this empty line.

   if (!parentLayoutObject->canHaveChildren())
     return false;
 
-  return m_node->layoutObjectIsNeeded(style());
+  // Make sure we keep track of "display: contents" styles.
+  ComputedStyle& style = this->style();

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

I think we need to manage this as reference counted, as I commented before.
Anyway, calling to styleRef() is what you want to get a ComputedStyle& style. I
think a "const" cast would be also helpful.

+  if (!m_node->layoutObjectIsNeeded(style)) {
+    if (style.display() == EDisplay::Contents)
+      m_node->storeDisplayContentsStyle(style);

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

We need to take care of references here.

+    return false;
+  }
+
+  return true;
 }
 
 ComputedStyle& LayoutTreeBuilderForElement::style() const {
@@ -156,7 +166,11 @@ void LayoutTreeBuilderForElement::createLayoutObject() {
 }
 
 void LayoutTreeBuilderForText::createLayoutObject() {
-  ComputedStyle& style = m_layoutObjectParent->mutableStyleRef();
+  ComputedStyle& style = *m_style;

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

The removed code was like that becase we wanted a mutable instance. I think we
need a similar workflow to clarify we are going to modify an instance that it
should be const otherwise.

+
+  DCHECK(m_style == m_layoutObjectParent->style() ||
+         toElement(LayoutTreeBuilderTraversal::parent(*m_node))
+             ->displayContentsStyle());
 
   DCHECK(m_node->textLayoutObjectIsNeeded(style, *m_layoutObjectParent));