Fix broken PrefService::preference_set() returning not all registered preferences.

chrome/browser/prefs/value_map_pref_store.h

Index: chrome/browser/prefs/value_map_pref_store.h
diff --git a/chrome/browser/prefs/value_map_pref_store.h b/chrome/browser/prefs/value_map_pref_store.h
index 20bf29021a4029d56e46506bd6059650fcd74dcd..a8b66c43f9259e37d4dcdc2cd71b4a252f949c27 100644
--- a/chrome/browser/prefs/value_map_pref_store.h
+++ b/chrome/browser/prefs/value_map_pref_store.h
@@ -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.
 
@@ -6,8 +6,6 @@
 #define CHROME_BROWSER_PREFS_VALUE_MAP_PREF_STORE_H_
 #pragma once
 
-#include <map>
-
 #include "base/basictypes.h"
 #include "base/observer_list.h"
 #include "chrome/browser/prefs/pref_value_map.h"
@@ -17,6 +15,9 @@
 // storing the preference values.
 class ValueMapPrefStore : public PrefStore {
  public:
+  typedef std::map<std::string, Value*>::iterator iterator;
+  typedef std::map<std::string, Value*>::const_iterator const_iterator;
+
   ValueMapPrefStore();
   virtual ~ValueMapPrefStore();
 
@@ -25,6 +26,11 @@ class ValueMapPrefStore : public PrefStore {
   virtual void AddObserver(PrefStore::Observer* observer);
   virtual void RemoveObserver(PrefStore::Observer* observer);
 
+  iterator begin();
+  iterator end();
+  const_iterator begin() const;
+  const_iterator end() const;
+
  protected:
   // Store a |value| for |key| in the store. Also generates an notification if
   // the value changed. Assumes ownership of |value|, which must be non-NULL.