Make comments about profile pointer in pref_value_store more informative.

chrome/browser/prefs/pref_value_store.h

 // Copyright (c) 2010 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_STORE_H_
 #define CHROME_BROWSER_PREFS_PREF_VALUE_STORE_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 169 matching lines @@
   //        preference values.
   //   |extension_prefs| contains preference values set by extensions.
   //   |command_line_prefs| contains preference values set by command-line
   //        switches.
   //   |user_prefs| contains all user-set preference values.
   //   |recommended_prefs| contains all recommended (policy) preference values.
   //   |default_prefs| contains application-default preference values. It must
   //        be non-null if any preferences are to be registered.
   //
   // The |profile| parameter is used to construct a replacement device
-  // management pref store in case of policy refresh, may be NULL for the local
-  // state preferences.
+  // management pref store. This is done after policy refresh when we swap out
+  // the policy pref stores for new ones, so the |profile| pointer needs to be
+  // kept around for then. It is safe to pass a NULL pointer for local state
+  // preferences.
   //
   // TODO(mnissler, danno): Refactor the pref store interface and refresh logic
-  // so refreshes can be handled by the pref store itself and the profile
-  // parameter be removed here.
+  // so refreshes can be handled by the pref store itself without swapping
+  // stores. This way we can get rid of the profile pointer here.
   //
   // This constructor should only be used internally, or by subclasses in
   // testing. The usual way to create a PrefValueStore is by creating a
   // PrefService.
   PrefValueStore(PrefStore* managed_platform_prefs,
                  PrefStore* device_management_prefs,
                  PrefStore* extension_prefs,
                  PrefStore* command_line_prefs,
                  PrefStore* user_prefs,
                  PrefStore* recommended_prefs,
@@ skipping 34 matching lines @@
       PrefStore* new_managed_platform_pref_store,
       PrefStore* new_device_management_pref_store,
       PrefStore* new_recommended_pref_store,
       AfterRefreshCallback* callback);
 
   scoped_ptr<PrefStore> pref_stores_[PrefNotifier::PREF_STORE_TYPE_MAX + 1];
 
   // A mapping of preference names to their registered types.
   PrefTypeMap pref_types_;
 
-  // The associated profile, if applicable.
+  // The associated profile, in case this value store is associated with a
+  // profile pref service. Used for recreating the device management pref store
+  // upon policy refresh.
   Profile* profile_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefValueStore);
 };
 
 #endif  // CHROME_BROWSER_PREFS_PREF_VALUE_STORE_H_