Change various helper classes to transition types to get CSSValue entirely onto the gc heap.

Source/core/html/parser/HTMLResourcePreloader.cpp

Index: Source/core/html/parser/HTMLResourcePreloader.cpp
diff --git a/Source/core/html/parser/HTMLResourcePreloader.cpp b/Source/core/html/parser/HTMLResourcePreloader.cpp
index b023fa930473072c3cfd70b5a18f92e8f530fe0a..e63c17a880bb6d3085726f54c79e41c07ccb9cdb 100644
--- a/Source/core/html/parser/HTMLResourcePreloader.cpp
+++ b/Source/core/html/parser/HTMLResourcePreloader.cpp
@@ -75,7 +75,7 @@ void HTMLResourcePreloader::takeAndPreload(PreloadRequestStream& r)
 
 static bool mediaAttributeMatches(Frame* frame, RenderStyle* renderStyle, const String& attributeValue)
 {
-    RefPtr<MediaQuerySet> mediaQueries = MediaQuerySet::create(attributeValue);
+    RefPtrWillBeRawPtr<MediaQuerySet> mediaQueries = MediaQuerySet::create(attributeValue);
     MediaQueryEvaluator mediaQueryEvaluator("screen", frame, renderStyle);
     return mediaQueryEvaluator.eval(mediaQueries.get());
 }