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

Source/core/html/shadow/DateTimeEditElement.h

Index: Source/core/html/shadow/DateTimeEditElement.h
diff --git a/Source/core/html/shadow/DateTimeEditElement.h b/Source/core/html/shadow/DateTimeEditElement.h
index 1025ff322a296d3898a7794f491042642fdca130..3d7d9767ee1a0e007f5915c9f942d80b9b5f43d0 100644
--- a/Source/core/html/shadow/DateTimeEditElement.h
+++ b/Source/core/html/shadow/DateTimeEditElement.h
@@ -30,6 +30,7 @@
 #include "core/html/forms/StepRange.h"
 #include "core/html/shadow/DateTimeFieldElement.h"
 #include "platform/DateComponents.h"
+#include "wtf/Allocator.h"
 
 namespace blink {
 
@@ -62,6 +63,7 @@ public:
     };
 
     struct LayoutParameters {
+        STACK_ALLOCATED();
         String dateTimeFormat;
         String fallbackDateTimeFormat;
         Locale& locale;