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

Source/core/dom/custom/CustomElementProcessingStack.h

Index: Source/core/dom/custom/CustomElementProcessingStack.h
diff --git a/Source/core/dom/custom/CustomElementProcessingStack.h b/Source/core/dom/custom/CustomElementProcessingStack.h
index df46534ef113164596cf9fe3231a91bc25e37d7b..90f9346b6a599501e2795beb6d8fa6e4d0884ea4 100644
--- a/Source/core/dom/custom/CustomElementProcessingStack.h
+++ b/Source/core/dom/custom/CustomElementProcessingStack.h
@@ -38,10 +38,12 @@
 namespace blink {
 
 class CORE_EXPORT CustomElementProcessingStack : public NoBaseWillBeGarbageCollectedFinalized<CustomElementProcessingStack> {
+    WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(CustomElementProcessingStack);
     WTF_MAKE_NONCOPYABLE(CustomElementProcessingStack);
 public:
     // This is stack allocated in many DOM callbacks. Make it cheap.
     class CallbackDeliveryScope {
+        STACK_ALLOCATED();
     public:
         CallbackDeliveryScope()
             : m_savedElementQueueStart(s_elementQueueStart)