[WIP] do something :-)

Source/core/css/StylePropertySet.cpp

Index: Source/core/css/StylePropertySet.cpp
diff --git a/Source/core/css/StylePropertySet.cpp b/Source/core/css/StylePropertySet.cpp
index 3173899f490f94b6618b069326d00e59bd2a2475..2b1f7b5deeb916567231745f7f71815cc4ffb013 100644
--- a/Source/core/css/StylePropertySet.cpp
+++ b/Source/core/css/StylePropertySet.cpp
@@ -31,6 +31,7 @@
 #include "core/css/parser/CSSParser.h"
 #include "core/frame/UseCounter.h"
 #include "platform/RuntimeEnabledFeatures.h"
+#include "wtf/SizeAssertions.h"
 #include "wtf/text/StringBuilder.h"
 
 #ifndef NDEBUG
@@ -496,10 +497,7 @@ unsigned StylePropertySet::averageSizeInBytes()
 }
 
 // See the function above if you need to update this.
-struct SameSizeAsStylePropertySet : public RefCountedWillBeGarbageCollectedFinalized<SameSizeAsStylePropertySet> {
-    unsigned bitfield;
-};
-static_assert(sizeof(StylePropertySet) == sizeof(SameSizeAsStylePropertySet), "StylePropertySet should stay small");
+ASSERT_SIZE(StylePropertySet, 8, 8);
 
 #ifndef NDEBUG
 void StylePropertySet::showStyle()