Styling slot fallback content with ::slotted()

third_party/WebKit/Source/core/css/SelectorChecker.cpp

Index: third_party/WebKit/Source/core/css/SelectorChecker.cpp
diff --git a/third_party/WebKit/Source/core/css/SelectorChecker.cpp b/third_party/WebKit/Source/core/css/SelectorChecker.cpp
index de3cc38e0a99f0391d090692b2529de9cd044b6b..6106d846915d593e0f9d9a0ef61aad7bd079e73f 100644
--- a/third_party/WebKit/Source/core/css/SelectorChecker.cpp
+++ b/third_party/WebKit/Source/core/css/SelectorChecker.cpp
@@ -123,8 +123,17 @@ static const HTMLSlotElement* FindSlotElementInScope(
   if (!context.scope)
     return context.element->AssignedSlot();
 
-  for (const HTMLSlotElement* slot = context.element->AssignedSlot(); slot;
-       slot = slot->AssignedSlot()) {
+  const HTMLSlotElement* slot = context.element->AssignedSlot();
+  if (!slot) {

[hayato, 2017/04/13 05:50:40]

Looks the dupe of code. It would be better to extract the similar code as a
function.

+    Element* parent = context.element->parentElement();
+    if (!parent || !isHTMLSlotElement(parent) ||
+        !toHTMLSlotElement(parent)->AssignedNodes().IsEmpty())
+      return nullptr;
+    slot = toHTMLSlotElement(parent);
+  }
+
+  // Find the slot element that matches the scope.
+  for (; slot; slot = slot->AssignedSlot()) {
     if (slot->GetTreeScope() == context.scope->GetTreeScope())
       return slot;
   }