Introduce incognito preference settings.

chrome/browser/prefs/pref_value_map.h

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_PREFS_PREF_VALUE_MAP_H_
 #define CHROME_BROWSER_PREFS_PREF_VALUE_MAP_H_
 #pragma once
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 
 class Value;
 
 // A generic string to value map used by the PrefStore implementations.
 class PrefValueMap {
  public:
+  typedef std::map<std::string, Value*>::iterator iterator;
+  typedef std::map<std::string, Value*>::const_iterator const_iterator;
+
   PrefValueMap();
   virtual ~PrefValueMap();
 
   // Gets the value for |key| and stores it in |value|. Ownership remains with
   // the map. Returns true if a value is present. If not, |value| is not
   // touched.
   bool GetValue(const std::string& key, Value** value) const;
 
   // Sets a new |value| for |key|. Takes ownership of |value|, which must be
   // non-NULL. Returns true if the value changed.
   bool SetValue(const std::string& key, Value* value);
 
   // Removes the value for |key| from the map. Returns true if a value was
   // removed.
   bool RemoveValue(const std::string& key);
 
   // Clears the map.
   void Clear();
 
+  iterator begin();
+  iterator end();
+  const_iterator begin() const;
+  const_iterator end() const;
+
   // Gets a boolean value for |key| and stores it in |value|. Returns true if
   // the value was found and of the proper type.
   bool GetBoolean(const std::string& key, bool* value) const;
 
   // Gets a string value for |key| and stores it in |value|. Returns true if
   // the value was found and of the proper type.
   bool GetString(const std::string& key, std::string* value) const;
 
   // Sets the value for |key| to the string |value|.
   void SetString(const std::string& key, const std::string& value);
 
   // Compares this value map against |other| and stores all key names that have
   // different values in |differing_keys|. This includes keys that are present
   // only in one of the maps.
   void GetDifferingKeys(const PrefValueMap* other,
                         std::vector<std::string>* differing_keys) const;
 
  private:
   typedef std::map<std::string, Value*> Map;
 
   Map prefs_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefValueMap);
 };
 
 #endif  // CHROME_BROWSER_PREFS_PREF_VALUE_MAP_H_