Evacuate ComputedStyle references from the CSS*Value hierarchy

third_party/WebKit/Source/core/html/canvas/CanvasFontCache.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 CanvasFontCache_h
 #define CanvasFontCache_h
 
 #include "core/CoreExport.h"
 #include "core/css/StylePropertySet.h"
 #include "platform/fonts/Font.h"
 #include "platform/heap/Handle.h"
 #include "public/platform/WebThread.h"
 #include "wtf/HashMap.h"
 #include "wtf/ListHashSet.h"
 #include "wtf/text/WTFString.h"
 #include <memory>
 
 namespace blink {
 
+class ComputedStyle;
 class Document;
 class FontCachePurgePreventer;
 
 class CORE_EXPORT CanvasFontCache final : public GarbageCollectedFinalized<CanvasFontCache>, public WebThread::TaskObserver {
 public:
     static CanvasFontCache* create(Document& document)
     {
         return new CanvasFontCache(document);
     }
 
@@ skipping 28 matching lines @@
     ListHashSet<String> m_fontLRUList;
     std::unique_ptr<FontCachePurgePreventer> m_mainCachePurgePreventer;
     Member<Document> m_document;
     RefPtr<ComputedStyle> m_defaultFontStyle;
     bool m_pruningScheduled;
 };
 
 } // namespace blink
 
 #endif