Move the FontFaceCache stored in CSSFontSelector to be stored in Document.

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
@@ skipping 6504 matching lines @@
   visitor->trace(m_elementDataCache);
   visitor->trace(m_useElementsNeedingUpdate);
   visitor->trace(m_timers);
   visitor->trace(m_templateDocument);
   visitor->trace(m_templateDocumentHost);
   visitor->trace(m_userActionElements);
   visitor->trace(m_svgExtensions);
   visitor->trace(m_timeline);
   visitor->trace(m_compositorPendingAnimations);
   visitor->trace(m_contextDocument);
+  visitor->trace(m_fontFaceCache);
   visitor->trace(m_canvasFontCache);
   visitor->trace(m_intersectionObserverController);
   visitor->trace(m_snapCoordinator);
   visitor->trace(m_resizeObserverController);
   visitor->trace(m_propertyRegistry);
   visitor->trace(m_styleReattachDataMap);
   Supplementable<Document>::trace(visitor);
   TreeScope::trace(visitor);
   ContainerNode::trace(visitor);
   ExecutionContext::trace(visitor);
@@ skipping 46 matching lines @@
 }
 
 void showLiveDocumentInstances() {
   WeakDocumentSet& set = liveDocumentSet();
   fprintf(stderr, "There are %u documents currently alive:\n", set.size());
   for (blink::Document* document : set)
     fprintf(stderr, "- Document %p URL: %s\n", document,
             document->url().getString().utf8().data());
 }
 #endif