[Typed-OM] Add compound type of CSSVariableReferenceValue and String with some tests

third_party/WebKit/Source/core/css/cssom/CSSTokenStreamValue.h

 // Copyright 2016 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 CSSTokenStreamValue_h
 #define CSSTokenStreamValue_h
 
 #include "bindings/core/v8/Iterable.h"
 #include "bindings/core/v8/StringOrCSSVariableReferenceValue.h"
 #include "core/css/cssom/CSSStyleValue.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 class CORE_EXPORT CSSTokenStreamValue final : public CSSStyleValue, public ValueIterable<StringOrCSSVariableReferenceValue> {
     WTF_MAKE_NONCOPYABLE(CSSTokenStreamValue);
     DEFINE_WRAPPERTYPEINFO();
 public:
-    static CSSTokenStreamValue* create(const Vector<String>& fragments)
+    static CSSTokenStreamValue* create(const HeapVector<StringOrCSSVariableReferenceValue>& fragments)
     {
         return new CSSTokenStreamValue(fragments);
     }
 
     CSSValue* toCSSValue() const override;
 
     StyleValueType type() const override { return TokenStreamType; }
 
-    String fragmentAtIndex(int index) const { return m_fragments.at(index); }
+    StringOrCSSVariableReferenceValue fragmentAtIndex(int index) const { return m_fragments.at(index); }
 
     size_t size() const { return m_fragments.size(); }
 
+    DEFINE_INLINE_VIRTUAL_TRACE()
+    {
+        visitor->trace(m_fragments);
+        CSSStyleValue::trace(visitor);
+    }
+
 protected:
-    CSSTokenStreamValue(const Vector<String>& fragments)
+    CSSTokenStreamValue(const HeapVector<StringOrCSSVariableReferenceValue>& fragments)
         : CSSStyleValue()
         , m_fragments(fragments)
     {
     }
 
 private:
     IterationSource* startIteration(ScriptState*, ExceptionState&) override;
 
-    Vector<String> m_fragments;
+    HeapVector<StringOrCSSVariableReferenceValue> m_fragments;
 };
 
 } // namespace blink
 
 #endif // CSSTokenStreamValue_h