Pass implementation object to supplemental classes by reference

Source/core/dom/ContextFeatures.h

 /*
  * Copyright (C) 2012 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 67 matching lines @@
 class ContextFeaturesClient {
     WTF_MAKE_FAST_ALLOCATED;
 public:
     static ContextFeaturesClient* empty();
 
     virtual ~ContextFeaturesClient() { }
     virtual bool isEnabled(Document*, ContextFeatures::FeatureType, bool defaultValue) { return defaultValue; }
     virtual void urlDidChange(Document*) { }
 };
 
-void provideContextFeaturesTo(Page*, ContextFeaturesClient*);
-void provideContextFeaturesToDocumentFrom(Document*, Page*);
+void provideContextFeaturesTo(Page&, ContextFeaturesClient*);
+void provideContextFeaturesToDocumentFrom(Document&, Page&);
 
 inline PassRefPtr<ContextFeatures> ContextFeatures::create(ContextFeaturesClient* client)
 {
     return adoptRef(new ContextFeatures(client));
 }
 
 inline bool ContextFeatures::isEnabled(Document* document, FeatureType type, bool defaultValue) const
 {
     if (!m_client)
         return defaultValue;
     return m_client->isEnabled(document, type, defaultValue);
 }
 
 inline void ContextFeatures::urlDidChange(Document* document)
 {
     // FIXME: The original code, commented out below, is obviously
     // wrong, but the seemingly correct fix of negating the test to
     // the more logical 'if (!m_client)' crashes the renderer.
     // See issue 294180
     //
     // if (m_client)
     //     return;
     // m_client->urlDidChange(document);
 }
 
 } // namespace WebCore
 
 #endif // ContextFeatures_h