Oilpan: move custom element objects to the heap.

Source/core/dom/custom/CustomElementDescriptor.h

Index: Source/core/dom/custom/CustomElementDescriptor.h
diff --git a/Source/core/dom/custom/CustomElementDescriptor.h b/Source/core/dom/custom/CustomElementDescriptor.h
index 7a3c6719bcc6a54a3e38842c7b67f5ee70c0eaa9..5d3a36a8423b69b62d18056bed4be97d93931f7e 100644
--- a/Source/core/dom/custom/CustomElementDescriptor.h
+++ b/Source/core/dom/custom/CustomElementDescriptor.h
@@ -31,6 +31,7 @@
 #ifndef CustomElementDescriptor_h
 #define CustomElementDescriptor_h
 
+#include "platform/heap/Handle.h"
 #include "wtf/HashTableDeletedValueType.h"
 #include "wtf/text/AtomicString.h"
 
@@ -41,6 +42,7 @@ struct CustomElementDescriptorHash;
 // A Custom Element descriptor is everything necessary to match a
 // Custom Element instance to a definition.
 class CustomElementDescriptor {
+    ALLOW_ONLY_INLINE_ALLOCATION();
 public:
     CustomElementDescriptor(const AtomicString& type, const AtomicString& namespaceURI, const AtomicString& localName)
         : m_type(type)