Shrink QualifiedNameImpl by 8 bytes on 64-bit platforms

Source/core/dom/QualifiedName.cpp

Index: Source/core/dom/QualifiedName.cpp
diff --git a/Source/core/dom/QualifiedName.cpp b/Source/core/dom/QualifiedName.cpp
index 264178ba1dbbab155c7f9f5e52648bb4b7f3238f..f669a905056d81aa85d66f813bf5d4ce63e56b40 100644
--- a/Source/core/dom/QualifiedName.cpp
+++ b/Source/core/dom/QualifiedName.cpp
@@ -34,6 +34,13 @@
 
 namespace blink {
 
+struct SameSizeAsQualifiedNameImpl : public RefCounted<SameSizeAsQualifiedNameImpl> {
+    unsigned bitfield;
+    void* pointers[4];
+};
+
+COMPILE_ASSERT(sizeof(QualifiedName::QualifiedNameImpl) == sizeof(SameSizeAsQualifiedNameImpl), qualified_name_impl_should_stay_small);
+
 static const int staticQualifiedNamesCount = HTMLNames::HTMLTagsCount + HTMLNames::HTMLAttrsCount
     + MathMLNames::MathMLTagsCount + MathMLNames::MathMLAttrsCount
     + SVGNames::SVGTagsCount + SVGNames::SVGAttrsCount