Have EditCommand classes deal with Document references, not pointers

Source/core/editing/EditCommand.h

 /*
  * Copyright (C) 2005, 2006, 2008 Apple 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 40 matching lines @@
     const VisibleSelection& endingSelection() const { return m_endingSelection; }
 
     virtual bool isSimpleEditCommand() const { return false; }
     virtual bool isCompositeEditCommand() const { return false; }
     virtual bool isEditCommandComposition() const { return false; }
     bool isTopLevelCommand() const { return !m_parent; }
 
     virtual void doApply() = 0;
 
 protected:
-    explicit EditCommand(Document*);
+    explicit EditCommand(Document&);
     EditCommand(Document*, const VisibleSelection&, const VisibleSelection&);
 
-    Document* document() const { return m_document.get(); }
+    Document& document() const { return *m_document.get(); }
     CompositeEditCommand* parent() const { return m_parent; }
     void setStartingSelection(const VisibleSelection&);
     void setEndingSelection(const VisibleSelection&);
 
 private:
     RefPtr<Document> m_document;
     VisibleSelection m_startingSelection;
     VisibleSelection m_endingSelection;
     CompositeEditCommand* m_parent;
 };
 
 enum ShouldAssumeContentIsAlwaysEditable {
     AssumeContentIsAlwaysEditable,
     DoNotAssumeContentIsAlwaysEditable,
 };
 
 class SimpleEditCommand : public EditCommand {
 public:
     virtual void doUnapply() = 0;
     virtual void doReapply(); // calls doApply()
 
 #ifndef NDEBUG
     virtual void getNodesInCommand(HashSet<Node*>&) = 0;
 #endif
 
 protected:
-    explicit SimpleEditCommand(Document* document) : EditCommand(document) { }
+    explicit SimpleEditCommand(Document& document) : EditCommand(document) { }
 
 #ifndef NDEBUG
     void addNodeAndDescendants(Node*, HashSet<Node*>&);
 #endif
 
 private:
     virtual bool isSimpleEditCommand() const OVERRIDE { return true; }
 };
 
 inline SimpleEditCommand* toSimpleEditCommand(EditCommand* command)
 {
     ASSERT(command);
     ASSERT_WITH_SECURITY_IMPLICATION(command->isSimpleEditCommand());
     return static_cast<SimpleEditCommand*>(command);
 }
 
 } // namespace WebCore
 
 #endif // EditCommand_h