Pass implementation object to supplemental classes by reference

Source/core/css/FontFaceSet.cpp

 /*
  * 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 100 matching lines @@
 
 private:
     FontsReadyPromiseResolver(ScriptPromise promise, ExecutionContext* context)
         : m_scriptState(ScriptState::current())
         , m_resolver(ScriptPromiseResolver::create(promise, context))
     { }
     ScriptState* m_scriptState;
     RefPtr<ScriptPromiseResolver> m_resolver;
 };
 
-FontFaceSet::FontFaceSet(Document* document)
-    : ActiveDOMObject(document)
+FontFaceSet::FontFaceSet(Document& document)
+    : ActiveDOMObject(&document)
     , m_loadingCount(0)
     , m_shouldFireLoadingEvent(false)
     , m_asyncRunner(this, &FontFaceSet::handlePendingEventsAndPromises)
 {
     suspendIfNeeded();
 }
 
 FontFaceSet::~FontFaceSet()
 {
 }
@@ skipping 388 matching lines @@
         return;
     m_recorded = true;
     blink::Platform::current()->histogramCustomCounts("WebFont.WebFontsInPage", m_count, 1, 100, 50);
 }
 
 static const char* supplementName()
 {
     return "FontFaceSet";
 }
 
-PassRefPtr<FontFaceSet> FontFaceSet::from(Document* document)
+PassRefPtr<FontFaceSet> FontFaceSet::from(Document& document)
 {
     RefPtr<FontFaceSet> fonts = static_cast<FontFaceSet*>(SupplementType::from(document, supplementName()));
     if (!fonts) {
         fonts = FontFaceSet::create(document);
         SupplementType::provideTo(document, supplementName(), fonts);
     }
 
     return fonts.release();
 }
 
-void FontFaceSet::didLayout(Document* document)
+void FontFaceSet::didLayout(Document& document)
 {
     if (FontFaceSet* fonts = static_cast<FontFaceSet*>(SupplementType::from(document, supplementName())))
         fonts->didLayout();
 }
 
 
 } // namespace WebCore