Fix g++ builds by avoiding early HeapSupplement<Document> instantiation.

third_party/WebKit/Source/core/css/FontFaceSet.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 12 matching lines @@
  * DAMAGE.
  */
 
 #ifndef FontFaceSet_h
 #define FontFaceSet_h
 
 #include "bindings/core/v8/Iterable.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "core/css/FontFace.h"
 #include "core/dom/ActiveDOMObject.h"
+#include "core/dom/Document.h"
 #include "core/events/EventListener.h"
 #include "core/events/EventTarget.h"
 #include "platform/AsyncMethodRunner.h"
 #include "platform/RefCountedSupplement.h"
+#include "platform/heap/Handle.h"
 #include "wtf/Allocator.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 #include "wtf/Vector.h"
 
 // Mac OS X 10.6 SDK defines check() macro that interfares with our check() method
 #ifdef check
 #undef check
 #endif
 
 namespace blink {
 
 class CSSFontFace;
 class CSSFontFaceSource;
 class CSSFontSelector;
 class Dictionary;
-class Document;
 class ExceptionState;
 class Font;
 class FontFaceCache;
 class FontResource;
 class ExecutionContext;
 
 using FontFaceSetIterable = PairIterable<RefPtrWillBeMember<FontFace>, RefPtrWillBeMember<FontFace>>;
 
 #if ENABLE(OILPAN)
 class FontFaceSet final : public EventTargetWithInlineData, public HeapSupplement<Document>, public ActiveDOMObject, public FontFaceSetIterable {
@@ skipping 112 matching lines @@
     WillBeHeapListHashSet<RefPtrWillBeMember<FontFace>> m_nonCSSConnectedFaces;
 
     PersistentWillBeMember<AsyncMethodRunner<FontFaceSet>> m_asyncRunner;
 
     FontLoadHistogram m_histogram;
 };
 
 } // namespace blink
 
 #endif // FontFaceSet_h