Reland of "Tracking reference filter mutation via SVGElementProxy"

third_party/WebKit/Source/core/css/CSSURIValue.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 CSSURIValue_h
 #define CSSURIValue_h
 
 #include "core/css/CSSValue.h"
-#include "core/fetch/DocumentResource.h"
+#include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class Document;
+class SVGElementProxy;
 
 class CSSURIValue : public CSSValue {
  public:
   static CSSURIValue* create(const String& str) { return new CSSURIValue(str); }
   ~CSSURIValue();
 
-  DocumentResource* cachedDocument() const { return m_document; }
-  DocumentResource* load(Document&) const;
+  SVGElementProxy& ensureElementProxy(Document&) const;
 
   const String& value() const { return m_url; }
   const String& url() const { return m_url; }
 
   String customCSSText() const;
 
-  bool loadRequested() const { return m_loadRequested; }
   bool equals(const CSSURIValue&) const;
 
   DECLARE_TRACE_AFTER_DISPATCH();
 
  private:
-  CSSURIValue(const String&);
+  explicit CSSURIValue(const String&);
 
   String m_url;
 
-  // Document cache.
-  mutable Member<DocumentResource> m_document;
-  mutable bool m_loadRequested;
+  mutable Member<SVGElementProxy> m_proxy;
 };
 
 DEFINE_CSS_VALUE_TYPE_CASTS(CSSURIValue, isURIValue());
 
 }  // namespace blink
 
 #endif  // CSSURIValue_h