Get rid of the ability to unregister preferences.

base/prefs/pref_service.cc

 // 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.
 
 #include "base/prefs/pref_service.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/file_path.h"
@@ skipping 40 matching lines @@
     : pref_notifier_(pref_notifier),
       pref_value_store_(pref_value_store),
       pref_registry_(pref_registry),
       user_pref_store_(user_prefs),
       read_error_callback_(read_error_callback) {
   pref_notifier_->SetPrefService(this);
 
   pref_registry_->SetRegistrationCallback(
       base::Bind(&PrefService::AddRegisteredPreference,
                  base::Unretained(this)));
-  pref_registry_->SetUnregistrationCallback(
-      base::Bind(&PrefService::RemoveRegisteredPreference,
-                 base::Unretained(this)));
   AddInitialPreferences();
 
   InitFromStorage(async);
 }
 
 PrefService::~PrefService() {
   DCHECK(CalledOnValidThread());
 
-  // Remove our callbacks, setting NULL ones.
+  // Remove our callback, setting a NULL one.
   pref_registry_->SetRegistrationCallback(PrefRegistry::RegistrationCallback());
-  pref_registry_->SetUnregistrationCallback(
-      PrefRegistry::UnregistrationCallback());
 
   // Reset pointers so accesses after destruction reliably crash.
   pref_value_store_.reset();
   pref_registry_ = NULL;
   user_pref_store_ = NULL;
   pref_notifier_.reset();
 }
 
 void PrefService::InitFromStorage(bool async) {
   if (!async) {
@@ skipping 263 matching lines @@
       needs_empty_value = true;
   } else if (orig_type == base::Value::TYPE_DICTIONARY) {
     const base::DictionaryValue* dict = NULL;
     if (default_value->GetAsDictionary(&dict) && !dict->empty())
       needs_empty_value = true;
   }
   if (needs_empty_value)
     user_pref_store_->MarkNeedsEmptyValue(path);
 }
 
-// TODO(joi): We can get rid of this once the ability to unregister
-// prefs has been removed.
-void PrefService::RemoveRegisteredPreference(const char* path) {
-  DCHECK(CalledOnValidThread());
-
-  prefs_map_.erase(path);
-}
-
 void PrefService::ClearPref(const char* path) {
   DCHECK(CalledOnValidThread());
 
   const Preference* pref = FindPreference(path);
   if (!pref) {
     NOTREACHED() << "Trying to clear an unregistered pref: " << path;
     return;
   }
   user_pref_store_->RemoveValue(path);
 }
@@ skipping 211 matching lines @@
       DCHECK(found_value->IsType(default_type));
       return found_value;
     } else {
       // Every registered preference has at least a default value.
       NOTREACHED() << "no valid value found for registered pref " << path;
     }
   }
 
   return NULL;
 }