[css-display] Support display: contents pseudo-elements.

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

Index: third_party/WebKit/Source/core/dom/FirstLetterPseudoElement.cpp
diff --git a/third_party/WebKit/Source/core/dom/FirstLetterPseudoElement.cpp b/third_party/WebKit/Source/core/dom/FirstLetterPseudoElement.cpp
index b08b73bcd942a3cfec37278981cf3dc2714df543..d9a7e72890df8ca3888ca3da7671f3404c6837b4 100644
--- a/third_party/WebKit/Source/core/dom/FirstLetterPseudoElement.cpp
+++ b/third_party/WebKit/Source/core/dom/FirstLetterPseudoElement.cpp
@@ -300,8 +300,10 @@ void FirstLetterPseudoElement::attachFirstLetterTextLayoutObjects() {
     remainingText = new LayoutTextFragment(
         nextLayoutObject->node(), oldText.impl(), length, remainingLength);
   } else {
+    PseudoElement* owningPseudo = nextLayoutObject->ownerPseudoElement();
     remainingText = LayoutTextFragment::createAnonymous(
-        *this, oldText.impl(), length, remainingLength);
+        owningPseudo ? *owningPseudo : *this, oldText.impl(), length,
+        remainingLength);

[rune, 2017/04/04 14:23:41]

I don't understand this. What is an ownerPseudoElement? Is it something specific
to first-letter?

[emilio, 2017/04/04 15:09:18]

So this is specific to first-letter because first-letter does this hacky thing
where it splits a text fragment into two. If that fragment happens to be
generated content inside a display: contents pseudo-element, we lost track of
the only hint that allows us to find them.

Perhaps I can take advantage of generated content always creating a text
fragment and mutate it instead, which may be cleaner and remove a bunch of
complexity. Let me try that.

Also, if we can guarantee that those LayoutObjects don't go away, we could just
track generated content in a std::vector<LayoutObject*> inside the
pseudo-element when it's a display: contents pseudo, but that sounds flacky.

   }
 
   remainingText->setFirstLetterPseudoElement(this);