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diff --git a/chromium/third_party/blink/renderer/core/css/properties/css_property_ref.h b/chromium/third_party/blink/renderer/core/css/properties/css_property_ref.h
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+++ b/chromium/third_party/blink/renderer/core/css/properties/css_property_ref.h
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+// Copyright 2018 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 THIRD_PARTY_BLINK_RENDERER_CORE_CSS_PROPERTIES_CSS_PROPERTY_REF_H_
+#define THIRD_PARTY_BLINK_RENDERER_CORE_CSS_PROPERTIES_CSS_PROPERTY_REF_H_
+
+#include "third_party/blink/renderer/core/css/properties/longhands/custom_property.h"
+
+namespace blink {
+
+class CSSPropertyName;
+class Document;
+
+// Use this class to acquire a reference to a CSSProperty instance. The
+// reference returned by GetProperty() may point to the embedded CustomProperty
+// object, hence this reference is only valid for the lifetime of the
+// CSSPropertyRef object.
+//
+// Usage:
+//
+//   CSSPropertyRef ref(some_string, document);
+//
+//   if (ref.IsValid()) {
+//     LOG(INFO) << ref.GetProperty().GetName();
+//   }
+//
+// Note that any CSSPropertyRef constructor may produce an invalid
+// CSSPropertyRef (e.g. if a non-existent property name is provided), so be
+// sure to always check IsValid() before calling GetProperty().
+class CORE_EXPORT CSSPropertyRef {
+  DISALLOW_NEW();
+
+ public:
+  // Look up (or create) a CSSProperty.
+  //
+  // If the incoming 'name' is not a CSS property, the CSSPropertyRef is
+  // invalid.
+  CSSPropertyRef(const String& name, const Document&);
+
+  // Like above, but will never produce an invalid CSSPropertyRef.
+  CSSPropertyRef(const CSSPropertyName&, const Document&);
+
+  // If you already have a CSSProperty& object, you may use it to get
+  // a CSSPropertyRef again.
+  //
+  // Note that the CSSProperty& returned by GetProperty() may be different
+  // than the incoming CSSProperty&.
+  //
+  // Note also that this CSSPropertyRef is invalid if the incoming CSSProperty&
+  // is the static Variable instance.
+  CSSPropertyRef(const CSSProperty&);
+
+  bool IsValid() const { return property_id_ != CSSPropertyInvalid; }
+
+  const CSSProperty& GetProperty() const {
+    DCHECK(IsValid());
+    if (property_id_ == CSSPropertyVariable)
+      return custom_property_;
+    return CSSProperty::Get(resolveCSSPropertyID(property_id_));
+  }
+
+  const CSSUnresolvedProperty& GetUnresolvedProperty() const {
+    if (isPropertyAlias(property_id_))
+      return *CSSUnresolvedProperty::GetAliasProperty(property_id_);
+    return GetProperty();
+  }
+
+  void Trace(blink::Visitor* visitor) { visitor->Trace(custom_property_); }
+
+ private:
+  CSSPropertyID property_id_;
+  CustomProperty custom_property_;
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_CSS_PROPERTIES_CSS_PROPERTY_REF_H_