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

Source/core/css/ComputedStyleCSSValueMapping.h

Index: Source/core/css/ComputedStyleCSSValueMapping.h
diff --git a/Source/core/css/ComputedStyleCSSValueMapping.h b/Source/core/css/ComputedStyleCSSValueMapping.h
index 76764c17212b5558688ae3c2257b97e7ed2de3f2..4de732d9a42ec9ea78a753466fede58c2e35e629 100644
--- a/Source/core/css/ComputedStyleCSSValueMapping.h
+++ b/Source/core/css/ComputedStyleCSSValueMapping.h
@@ -7,6 +7,7 @@
 
 #include "core/CSSPropertyNames.h"
 #include "core/css/CSSValue.h"
+#include "wtf/Allocator.h"
 
 namespace blink {
 
@@ -19,6 +20,7 @@ class StyleColor;
 class Node;
 
 class ComputedStyleCSSValueMapping {
+    STATIC_ONLY(ComputedStyleCSSValueMapping);
 public:
     // FIXME: Resolve computed auto alignment in applyProperty/ComputedStyle and remove this non-const styledNode parameter.
     static PassRefPtrWillBeRawPtr<CSSValue> get(CSSPropertyID, const ComputedStyle&, const LayoutObject* = nullptr, Node* styledNode = nullptr, bool allowVisitedStyle = false);