Make classes and structures in core/dom fast-allocated.

Source/core/dom/custom/CustomElementCallbackQueue.h

Index: Source/core/dom/custom/CustomElementCallbackQueue.h
diff --git a/Source/core/dom/custom/CustomElementCallbackQueue.h b/Source/core/dom/custom/CustomElementCallbackQueue.h
index 7ddc5abfa3c5e37d76f6eaf83cc1c34983040e94..7af6041860600564a06f64210c54a65869001126 100644
--- a/Source/core/dom/custom/CustomElementCallbackQueue.h
+++ b/Source/core/dom/custom/CustomElementCallbackQueue.h
@@ -46,6 +46,7 @@ namespace blink {
 // well as callbacks.
 class CustomElementCallbackQueue : public NoBaseWillBeGarbageCollectedFinalized<CustomElementCallbackQueue> {
     WTF_MAKE_NONCOPYABLE(CustomElementCallbackQueue);
+    WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(CustomElementCallbackQueue);
 public:
     static PassOwnPtrWillBeRawPtr<CustomElementCallbackQueue> create(PassRefPtrWillBeRawPtr<Element>);