No longer register app window placement preference keys on the fly.

base/prefs/pref_service.h

 // Copyright (c) 2012 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.
 
 // This provides a way to access the application's current preferences.
 
 // Chromium settings and storage represent user-selected preferences and
 // information and MUST not be extracted, overwritten or modified except
 // through Chromium defined APIs.
 
@@ skipping 252 matching lines @@
   // register all preferences for a class Xyz up front in a static
   // Xyz::RegisterPrefs function, which gets invoked early in the
   // application's start-up, before a PrefService is created.
   //
   // As an example, prefs registration in Chrome is triggered by the
   // functions chrome::RegisterPrefs (for global preferences) and
   // chrome::RegisterProfilePrefs (for user-specific preferences)
   // implemented in chrome/browser/prefs/browser_prefs.cc.
   PrefRegistry* DeprecatedGetPrefRegistry();
 
+  // This is only to be used to migrate unregistered prefs to become registered.

[Bernhard Bauer, 2014/09/04 11:06:02]

One thing we could do to ensure no one else uses this method would be to make it
private and friend the caller. WDYT?

[dgrogan, 2014/09/04 20:26:33]

Changed (for this patchset, at least). I don't like two things about it. (1)
When we remove the method it will be easy to forget about the "friend" line. (2)
The declarations are ugly and indicate a layering violation, though none exists.
I'm going to look into using PrefFilter to obviate this issue.

+  // TODO(dgrogan): Remove after a suitable migration period. See

[Bernhard Bauer, 2014/09/04 11:06:02]

Can you add what a suitable migration period is? (E.g. which milestone) That
way, even if we both forget about this, someone else who comes across this code
in ten years can fix it.

[dgrogan, 2014/09/04 20:26:32]

Done.

+  // http://crbug.com/167256.
+  scoped_ptr<base::DictionaryValue> GetBrowserDictionary() const;

[dgrogan, 2014/09/04 00:50:51]

This is the ugliest. See browser_ui_prefs.cc for its usage.

+
  protected:
   // The PrefNotifier handles registering and notifying preference observers.
   // It is created and owned by this PrefService. Subclasses may access it for
   // unit testing.
   scoped_ptr<PrefNotifierImpl> pref_notifier_;
 
   // The PrefValueStore provides prioritized preference values. It is owned by
   // this PrefService. Subclasses may access it for unit testing.
   scoped_ptr<PrefValueStore> pref_value_store_;
 
@@ skipping 67 matching lines @@
 
   // Local cache of registered Preference objects. The pref_registry_
   // is authoritative with respect to what the types and default values
   // of registered preferences are.
   mutable PreferenceMap prefs_map_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefService);
 };
 
 #endif  // BASE_PREFS_PREF_SERVICE_H_