Remove trace() methods for stack-only classes.

third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CSSVariableResolver_h
 #define CSSVariableResolver_h
 
 #include "core/CSSPropertyNames.h"
 #include "core/css/parser/CSSParserToken.h"
 #include "wtf/HashSet.h"
@@ skipping 19 matching lines @@
 
   // Shorthand properties are not supported.
   static const CSSValue* resolveVariableReferences(
       const StyleResolverState&,
       CSSPropertyID,
       const CSSValue&,
       bool disallowAnimationTainted);
 
   static void computeRegisteredVariables(const StyleResolverState&);
 
-  DECLARE_TRACE();
-
  private:
   CSSVariableResolver(const StyleResolverState&);
 
   static const CSSValue* resolvePendingSubstitutions(
       const StyleResolverState&,
       CSSPropertyID,
       const CSSPendingSubstitutionValue&,
       bool disallowAnimationTainted);
   static const CSSValue* resolveVariableReferences(
       const StyleResolverState&,
@@ skipping 38 matching lines @@
   HashSet<AtomicString> m_variablesSeen;
   // Resolution doesn't finish when a cycle is detected. Fallbacks still
   // need to be tracked for additional cycles, and invalidation only
   // applies back to cycle starts.
   HashSet<AtomicString> m_cycleStartPoints;
 };
 
 }  // namespace blink
 
 #endif  // CSSVariableResolver