Dispatch slotchange events in "notify mutation observers" steps

third_party/WebKit/Source/core/dom/MutationObserver.h

Index: third_party/WebKit/Source/core/dom/MutationObserver.h
diff --git a/third_party/WebKit/Source/core/dom/MutationObserver.h b/third_party/WebKit/Source/core/dom/MutationObserver.h
index 6b35d7312eb4cd89833b85ed2231b91c3dee1c95..4c9f27b6d4270e0408802d569a1849a82636fae8 100644
--- a/third_party/WebKit/Source/core/dom/MutationObserver.h
+++ b/third_party/WebKit/Source/core/dom/MutationObserver.h
@@ -41,6 +41,7 @@
 namespace blink {
 
 class ExceptionState;
+class HTMLSlotElement;
 class MutationCallback;
 class MutationObserver;
 class MutationObserverInit;
@@ -81,6 +82,7 @@ class CORE_EXPORT MutationObserver final
   static MutationObserver* create(MutationCallback*);
   static void resumeSuspendedObservers();
   static void deliverMutations();
+  static void enqueueSlotChange(HTMLSlotElement&);
 
   ~MutationObserver();