Make blink classes and structures in core/css fast-allocated

Source/core/css/DocumentFontFaceSet.h

Index: Source/core/css/DocumentFontFaceSet.h
diff --git a/Source/core/css/DocumentFontFaceSet.h b/Source/core/css/DocumentFontFaceSet.h
index 0c0d31c9952c6496da01eea8bc29cd42ef946190..21b65ea63c69cbe4a477969498f5014260bfc1f6 100644
--- a/Source/core/css/DocumentFontFaceSet.h
+++ b/Source/core/css/DocumentFontFaceSet.h
@@ -27,6 +27,7 @@
 #define DocumentFontFaceSet_h
 
 #include "platform/heap/Handle.h"
+#include "wtf/Allocator.h"
 #include "wtf/PassRefPtr.h"
 
 namespace blink {
@@ -35,6 +36,7 @@ class Document;
 class FontFaceSet;
 
 class DocumentFontFaceSet {
+    STATIC_ONLY(DocumentFontFaceSet);
 public:
     static PassRefPtrWillBeRawPtr<FontFaceSet> fonts(Document&);
 };