Annotate ScriptWrappable-embedding singletons.

third_party/WebKit/Source/core/css/CSSStyleRule.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2005, 2006, 2008, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 17 matching lines @@
 #include "core/css/StyleRule.h"
 #include "core/css/parser/CSSParser.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace blink {
 
 using SelectorTextCache =
     PersistentHeapHashMap<WeakMember<const CSSStyleRule>, String>;
 
 static SelectorTextCache& selectorTextCache() {
+  ALLOW_UNSAFE_SINGLETON()
   DEFINE_STATIC_LOCAL(SelectorTextCache, cache, ());
   return cache;
 }
 
 CSSStyleRule::CSSStyleRule(StyleRule* styleRule, CSSStyleSheet* parent)
     : CSSRule(parent), m_styleRule(styleRule) {}
 
 CSSStyleRule::~CSSStyleRule() {}
 
 CSSStyleDeclaration* CSSStyleRule::style() const {
@@ skipping 72 matching lines @@
   CSSRule::trace(visitor);
 }
 
 DEFINE_TRACE_WRAPPERS(CSSStyleRule) {
   visitor->traceWrappers(parentRule());
   visitor->traceWrappers(parentStyleSheet());
   CSSRule::traceWrappers(visitor);
 }
 
 }  // namespace blink