Introduce incognito preference settings.

chrome/browser/prefs/pref_value_map.cc

Index: chrome/browser/prefs/pref_value_map.cc
diff --git a/chrome/browser/prefs/pref_value_map.cc b/chrome/browser/prefs/pref_value_map.cc
index 6e7bf79e160ab9683d37126976f089ef88a5ee3b..0857f6dc22b7000ce4765d6a7e4657c8fe08576d 100644
--- a/chrome/browser/prefs/pref_value_map.cc
+++ b/chrome/browser/prefs/pref_value_map.cc
@@ -1,4 +1,4 @@
-// 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.
 
@@ -58,6 +58,22 @@ void PrefValueMap::Clear() {
   prefs_.clear();
 }
 
+PrefValueMap::iterator PrefValueMap::begin() {
+  return prefs_.begin();
+}
+
+PrefValueMap::iterator PrefValueMap::end() {
+  return prefs_.end();
+}
+
+PrefValueMap::const_iterator PrefValueMap::begin() const {
+  return prefs_.begin();
+}
+
+PrefValueMap::const_iterator PrefValueMap::end() const {
+  return prefs_.end();
+}
+
 bool PrefValueMap::GetBoolean(const std::string& key,
                               bool* value) const {
   Value* stored_value = NULL;