Clean up pref change notification handling.

chrome/browser/prefs/pref_value_store.cc

 // 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.
 
 #include "chrome/browser/prefs/pref_value_store.h"
 
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/policy/configuration_policy_pref_store.h"
-#include "chrome/browser/prefs/command_line_pref_store.h"
-#include "chrome/browser/prefs/in_memory_pref_store.h"
-#include "chrome/common/json_pref_store.h"
+#include "chrome/browser/prefs/pref_notifier.h"
 #include "chrome/common/notification_service.h"
 
-namespace {
-
-// Returns true if the actual value is a valid type for the expected type when
-// found in the given store.
-bool IsValidType(Value::ValueType expected, Value::ValueType actual,
-                 PrefNotifier::PrefStoreType store) {
-  if (expected == actual)
-    return true;
-
-  // Dictionaries and lists are allowed to hold TYPE_NULL values too, but only
-  // in the default pref store.
-  if (store == PrefNotifier::DEFAULT_STORE &&
-      actual == Value::TYPE_NULL &&
-      (expected == Value::TYPE_DICTIONARY || expected == Value::TYPE_LIST)) {
-    return true;
-  }
-  return false;
+PrefValueStore::PrefStoreKeeper::PrefStoreKeeper()
+    : pref_value_store_(NULL),
+      type_(PrefValueStore::INVALID_STORE) {
 }
 
-}  // namespace
+PrefValueStore::PrefStoreKeeper::~PrefStoreKeeper() {
+  if (pref_store_.get())
+    pref_store_->RemoveObserver(this);
+}
 
-// static
-PrefValueStore* PrefValueStore::CreatePrefValueStore(
-    const FilePath& pref_filename,
-    Profile* profile,
-    bool user_only) {
-  using policy::ConfigurationPolicyPrefStore;
-  ConfigurationPolicyPrefStore* managed = NULL;
-  ConfigurationPolicyPrefStore* device_management = NULL;
-  CommandLinePrefStore* command_line = NULL;
-  ConfigurationPolicyPrefStore* recommended = NULL;
+void PrefValueStore::PrefStoreKeeper::Initialize(
+    PrefValueStore* store,
+    PrefStore* pref_store,
+    PrefValueStore::PrefStoreType type) {
+  if (pref_store_.get())
+    pref_store_->RemoveObserver(this);
+  type_ = type;
+  pref_value_store_ = store;
+  pref_store_.reset(pref_store);
+  if (pref_store_.get())
+    pref_store_->AddObserver(this);
+}
 
-  JsonPrefStore* user = new JsonPrefStore(
-      pref_filename,
-      BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE));
-  InMemoryPrefStore* extension = new InMemoryPrefStore();
-  InMemoryPrefStore* default_store = new InMemoryPrefStore();
+void PrefValueStore::PrefStoreKeeper::OnPrefValueChanged(
+    const std::string& key) {
+  pref_value_store_->OnPrefValueChanged(type_, key);
+}
 
-  if (!user_only) {
-    managed =
-        ConfigurationPolicyPrefStore::CreateManagedPlatformPolicyPrefStore();
-    device_management =
-        ConfigurationPolicyPrefStore::CreateDeviceManagementPolicyPrefStore(
-            profile);
-    command_line = new CommandLinePrefStore(CommandLine::ForCurrentProcess());
-    recommended =
-        ConfigurationPolicyPrefStore::CreateRecommendedPolicyPrefStore();
-  }
-  return new PrefValueStore(managed, device_management, extension,
-                            command_line, user, recommended, default_store,
-                            profile);
+void PrefValueStore::PrefStoreKeeper::OnInitializationCompleted() {
+  pref_value_store_->OnInitializationCompleted(type_);
+}
+
+PrefValueStore::PrefValueStore(PrefStore* managed_platform_prefs,
+                               PrefStore* device_management_prefs,
+                               PrefStore* extension_prefs,
+                               PrefStore* command_line_prefs,
+                               PrefStore* user_prefs,
+                               PrefStore* recommended_prefs,
+                               PrefStore* default_prefs,
+                               PrefNotifier* pref_notifier,
+                               Profile* profile)
+    : pref_notifier_(pref_notifier),
+      profile_(profile) {
+  // NULL default pref store is usually bad, but may be OK for some unit tests.
+  if (!default_prefs)
+    LOG(WARNING) << "default pref store is null";
+  InitPrefStore(MANAGED_PLATFORM_STORE, managed_platform_prefs);
+  InitPrefStore(DEVICE_MANAGEMENT_STORE, device_management_prefs);
+  InitPrefStore(EXTENSION_STORE, extension_prefs);
+  InitPrefStore(COMMAND_LINE_STORE, command_line_prefs);
+  InitPrefStore(USER_STORE, user_prefs);
+  InitPrefStore(RECOMMENDED_STORE, recommended_prefs);
+  InitPrefStore(DEFAULT_STORE, default_prefs);
+
+  // TODO(mnissler): Remove after policy refresh cleanup.
+  registrar_.Add(this,
+                 NotificationType(NotificationType::POLICY_CHANGED),
+                 NotificationService::AllSources());
+
+  CheckInitializationCompleted();
 }
 
 PrefValueStore::~PrefValueStore() {}
 
 bool PrefValueStore::GetValue(const std::string& name,
                               Value** out_value) const {
   // Check the |PrefStore|s in order of their priority from highest to lowest
   // to find the value of the preference described by the given preference name.
-  for (size_t i = 0; i <= PrefNotifier::PREF_STORE_TYPE_MAX; ++i) {
-    if (GetValueFromStore(name.c_str(),
-                          static_cast<PrefNotifier::PrefStoreType>(i),
+  for (size_t i = 0; i <= PREF_STORE_TYPE_MAX; ++i) {
+    if (GetValueFromStore(name.c_str(), static_cast<PrefStoreType>(i),
                           out_value))
       return true;
   }
   return false;
 }
 
 bool PrefValueStore::GetUserValue(const std::string& name,
                                   Value** out_value) const {
-  return GetValueFromStore(name.c_str(), PrefNotifier::USER_STORE, out_value);
+  return GetValueFromStore(name.c_str(), USER_STORE, out_value);
 }
 
 void PrefValueStore::RegisterPreferenceType(const std::string& name,
                                             Value::ValueType type) {
   pref_types_[name] = type;
 }
 
 Value::ValueType PrefValueStore::GetRegisteredType(
     const std::string& name) const {
   PrefTypeMap::const_iterator found = pref_types_.find(name);
   if (found == pref_types_.end())
     return Value::TYPE_NULL;
   return found->second;
 }
 
 bool PrefValueStore::WritePrefs() {
   bool success = true;
-  for (size_t i = 0; i <= PrefNotifier::PREF_STORE_TYPE_MAX; ++i) {
-    if (pref_stores_[i].get())
-      success = pref_stores_[i]->WritePrefs() && success;
+  for (size_t i = 0; i <= PREF_STORE_TYPE_MAX; ++i) {
+    PrefStore* store = GetPrefStore(static_cast<PrefStoreType>(i));
+    if (store)
+      success = store->WritePrefs() && success;
   }
   return success;
 }
 
 void PrefValueStore::ScheduleWritePrefs() {
-  for (size_t i = 0; i <= PrefNotifier::PREF_STORE_TYPE_MAX; ++i) {
-    if (pref_stores_[i].get())
-      pref_stores_[i]->ScheduleWritePrefs();
+  for (size_t i = 0; i <= PREF_STORE_TYPE_MAX; ++i) {
+    PrefStore* store = GetPrefStore(static_cast<PrefStoreType>(i));
+    if (store)
+      store->ScheduleWritePrefs();
   }
 }
 
 PrefStore::PrefReadError PrefValueStore::ReadPrefs() {
   PrefStore::PrefReadError result = PrefStore::PREF_READ_ERROR_NONE;
-  for (size_t i = 0; i <= PrefNotifier::PREF_STORE_TYPE_MAX; ++i) {
-    if (pref_stores_[i].get()) {
-      PrefStore::PrefReadError this_error = pref_stores_[i]->ReadPrefs();
+  for (size_t i = 0; i <= PREF_STORE_TYPE_MAX; ++i) {
+    PrefStore* store = GetPrefStore(static_cast<PrefStoreType>(i));
+    if (store) {
+      PrefStore::PrefReadError this_error = store->ReadPrefs();
       if (result == PrefStore::PREF_READ_ERROR_NONE)
         result = this_error;
     }
   }
 
   if (HasPolicyConflictingUserProxySettings()) {
     LOG(WARNING) << "user-requested proxy options have been overridden"
                  << " by a proxy configuration specified in a centrally"
                  << " administered policy.";
   }
 
   // TODO(markusheintz): Return a better error status: maybe a struct with
   // the error status of all PrefStores.
   return result;
 }
 
 bool PrefValueStore::HasPrefPath(const char* path) const {
   Value* tmp_value = NULL;
   const std::string name(path);
   bool rv = GetValue(name, &tmp_value);
   // Merely registering a pref doesn't count as "having" it: we require a
   // non-default value set.
   return rv && !PrefValueFromDefaultStore(path);
 }
 
-bool PrefValueStore::PrefHasChanged(const char* path,
-                                    PrefNotifier::PrefStoreType new_store) {
-  DCHECK(new_store != PrefNotifier::INVALID_STORE);
-  // If we get a change notification about an unregistered preference,
-  // discard it silently because there cannot be any listeners.
-  if (pref_types_.find(path) == pref_types_.end())
-    return false;
+void PrefValueStore::NotifyPrefChanged(
+    const char* path,
+    PrefValueStore::PrefStoreType new_store) {
+  DCHECK(new_store != INVALID_STORE);
 
-  // Replying that the pref has changed may cause problems, but it's the safer
-  // choice.
-  if (new_store == PrefNotifier::INVALID_STORE)
-    return true;
+  // If this pref is not registered, just discard the notification.
+  if (!pref_types_.count(path))
+    return;
 
-  PrefNotifier::PrefStoreType controller = ControllingPrefStoreForPref(path);
-  DCHECK(controller != PrefNotifier::INVALID_STORE)
-      << "Invalid controller for path " << path;
-  if (controller == PrefNotifier::INVALID_STORE)
-    return true;
+  bool changed = true;
+  // Replying that the pref has changed in case the new store is invalid may
+  // cause problems, but it's the safer choice.
+  if (new_store != INVALID_STORE) {
+    PrefStoreType controller = ControllingPrefStoreForPref(path);
+    DCHECK(controller != INVALID_STORE);
+    // If the pref is controlled by a higher-priority store, its effective value
+    // cannot have changed.
+    if (controller != INVALID_STORE &&
+        controller < new_store) {
+      changed = false;
+    }
+  }
 
-  // If the pref is controlled by a higher-priority store, its effective value
-  // cannot have changed.
-  if (controller < new_store)
-    return false;
-
-  // Otherwise, we take the pref store's word that something changed.
-  return true;
+  if (changed)
+    pref_notifier_->OnPreferenceChanged(path);
 }
 
-// Note the |DictionaryValue| referenced by the |PrefStore| USER_STORE
-// (returned by the method prefs()) takes the ownership of the Value referenced
-// by in_value.
-bool PrefValueStore::SetUserPrefValue(const char* name, Value* in_value) {
+void PrefValueStore::SetUserPrefValue(const char* name, Value* in_value) {
+  DCHECK(in_value);
   Value* old_value = NULL;
-  pref_stores_[PrefNotifier::USER_STORE]->prefs()->Get(name, &old_value);
-  bool value_changed = !(old_value && old_value->Equals(in_value));
+  GetPrefStore(USER_STORE)->prefs()->Get(name, &old_value);
+  bool value_changed = !old_value || !old_value->Equals(in_value);
+  GetPrefStore(USER_STORE)->prefs()->Set(name, in_value);
 
-  pref_stores_[PrefNotifier::USER_STORE]->prefs()->Set(name, in_value);
-  return value_changed;
+  if (value_changed)
+    NotifyPrefChanged(name, USER_STORE);
 }
 
-// Note the |DictionaryValue| referenced by the |PrefStore| DEFAULT_STORE
-// (returned by the method prefs()) takes the ownership of the Value referenced
-// by in_value.
-void PrefValueStore::SetDefaultPrefValue(const char* name, Value* in_value) {
-  pref_stores_[PrefNotifier::DEFAULT_STORE]->prefs()->Set(name, in_value);
+void PrefValueStore::SetUserPrefValueSilently(const char* name,
+                                              Value* in_value) {
+  DCHECK(in_value);
+  GetPrefStore(USER_STORE)->prefs()->Set(name, in_value);
 }
 
-bool PrefValueStore::ReadOnly() {
-  return pref_stores_[PrefNotifier::USER_STORE]->ReadOnly();
+bool PrefValueStore::ReadOnly() const {
+  return GetPrefStore(USER_STORE)->ReadOnly();
 }
 
-bool PrefValueStore::RemoveUserPrefValue(const char* name) {
-  if (pref_stores_[PrefNotifier::USER_STORE].get()) {
-    return pref_stores_[PrefNotifier::USER_STORE]->prefs()->Remove(name, NULL);
+void PrefValueStore::RemoveUserPrefValue(const char* name) {
+  if (GetPrefStore(USER_STORE)) {
+    if (GetPrefStore(USER_STORE)->prefs()->Remove(name, NULL))
+      NotifyPrefChanged(name, USER_STORE);
+  }
+}
+
+bool PrefValueStore::PrefValueInManagedPlatformStore(const char* name) const {
+  return PrefValueInStore(name, MANAGED_PLATFORM_STORE);
+}
+
+bool PrefValueStore::PrefValueInDeviceManagementStore(const char* name) const {
+  return PrefValueInStore(name, DEVICE_MANAGEMENT_STORE);
+}
+
+bool PrefValueStore::PrefValueInExtensionStore(const char* name) const {
+  return PrefValueInStore(name, EXTENSION_STORE);
+}
+
+bool PrefValueStore::PrefValueInUserStore(const char* name) const {
+  return PrefValueInStore(name, USER_STORE);
+}
+
+bool PrefValueStore::PrefValueFromExtensionStore(const char* name) const {
+  return ControllingPrefStoreForPref(name) == EXTENSION_STORE;
+}
+
+bool PrefValueStore::PrefValueFromUserStore(const char* name) const {
+  return ControllingPrefStoreForPref(name) == USER_STORE;
+}
+
+bool PrefValueStore::PrefValueFromDefaultStore(const char* name) const {
+  return ControllingPrefStoreForPref(name) == DEFAULT_STORE;
+}
+
+bool PrefValueStore::PrefValueUserModifiable(const char* name) const {
+  PrefStoreType effective_store = ControllingPrefStoreForPref(name);
+  return effective_store >= USER_STORE ||
+         effective_store == INVALID_STORE;
+}
+
+bool PrefValueStore::HasPolicyConflictingUserProxySettings() const {
+  using policy::ConfigurationPolicyPrefStore;
+  ConfigurationPolicyPrefStore::ProxyPreferenceSet proxy_prefs;
+  ConfigurationPolicyPrefStore::GetProxyPreferenceSet(&proxy_prefs);
+  ConfigurationPolicyPrefStore::ProxyPreferenceSet::const_iterator i;
+  for (i = proxy_prefs.begin(); i != proxy_prefs.end(); ++i) {
+    if ((PrefValueInManagedPlatformStore(*i) ||
+         PrefValueInDeviceManagementStore(*i)) &&
+        PrefValueInStoreRange(*i,
+                              COMMAND_LINE_STORE,
+                              USER_STORE))
+      return true;
   }
   return false;
 }
 
-bool PrefValueStore::PrefValueInManagedPlatformStore(const char* name) const {
-  return PrefValueInStore(name, PrefNotifier::MANAGED_PLATFORM_STORE);
+// Returns true if the actual value is a valid type for the expected type when
+// found in the given store.
+bool PrefValueStore::IsValidType(Value::ValueType expected,
+                                 Value::ValueType actual,
+                                 PrefValueStore::PrefStoreType store) {
+  if (expected == actual)
+    return true;
+
+  // Dictionaries and lists are allowed to hold TYPE_NULL values too, but only
+  // in the default pref store.
+  if (store == DEFAULT_STORE &&
+      actual == Value::TYPE_NULL &&
+      (expected == Value::TYPE_DICTIONARY || expected == Value::TYPE_LIST)) {
+    return true;
+  }
+  return false;
 }
 
-bool PrefValueStore::PrefValueInDeviceManagementStore(const char* name) const {
-  return PrefValueInStore(name, PrefNotifier::DEVICE_MANAGEMENT_STORE);
-}
-
-bool PrefValueStore::PrefValueInExtensionStore(const char* name) const {
-  return PrefValueInStore(name, PrefNotifier::EXTENSION_STORE);
-}
-
-bool PrefValueStore::PrefValueInUserStore(const char* name) const {
-  return PrefValueInStore(name, PrefNotifier::USER_STORE);
+bool PrefValueStore::PrefValueInStore(
+    const char* name,
+    PrefValueStore::PrefStoreType store) const {
+  // Declare a temp Value* and call GetValueFromStore,
+  // ignoring the output value.
+  Value* tmp_value = NULL;
+  return GetValueFromStore(name, store, &tmp_value);
 }
 
 bool PrefValueStore::PrefValueInStoreRange(
     const char* name,
-    PrefNotifier::PrefStoreType first_checked_store,
-    PrefNotifier::PrefStoreType last_checked_store) {
+    PrefValueStore::PrefStoreType first_checked_store,
+    PrefValueStore::PrefStoreType last_checked_store) const {
   if (first_checked_store > last_checked_store) {
     NOTREACHED();
     return false;
   }
 
   for (size_t i = first_checked_store;
        i <= static_cast<size_t>(last_checked_store); ++i) {
-    if (PrefValueInStore(name, static_cast<PrefNotifier::PrefStoreType>(i)))
+    if (PrefValueInStore(name, static_cast<PrefStoreType>(i)))
       return true;
   }
   return false;
 }
 
-bool PrefValueStore::PrefValueFromExtensionStore(const char* name) const {
-  return ControllingPrefStoreForPref(name) == PrefNotifier::EXTENSION_STORE;
+PrefValueStore::PrefStoreType PrefValueStore::ControllingPrefStoreForPref(
+    const char* name) const {
+  for (size_t i = 0; i <= PREF_STORE_TYPE_MAX; ++i) {
+    if (PrefValueInStore(name, static_cast<PrefStoreType>(i)))
+      return static_cast<PrefStoreType>(i);
+  }
+  return INVALID_STORE;
 }
 
-bool PrefValueStore::PrefValueFromUserStore(const char* name) const {
-  return ControllingPrefStoreForPref(name) == PrefNotifier::USER_STORE;
-}
-
-bool PrefValueStore::PrefValueFromDefaultStore(const char* name) const {
-  return ControllingPrefStoreForPref(name) == PrefNotifier::DEFAULT_STORE;
-}
-
-bool PrefValueStore::PrefValueUserModifiable(const char* name) const {
-  PrefNotifier::PrefStoreType effective_store =
-      ControllingPrefStoreForPref(name);
-  return effective_store >= PrefNotifier::USER_STORE ||
-         effective_store == PrefNotifier::INVALID_STORE;
-}
-
-PrefNotifier::PrefStoreType PrefValueStore::ControllingPrefStoreForPref(
-    const char* name) const {
-  for (int i = 0; i <= PrefNotifier::PREF_STORE_TYPE_MAX; ++i) {
-    if (PrefValueInStore(name, static_cast<PrefNotifier::PrefStoreType>(i)))
-      return static_cast<PrefNotifier::PrefStoreType>(i);
-  }
-  return PrefNotifier::INVALID_STORE;
-}
-
-bool PrefValueStore::PrefValueInStore(
-    const char* name,
-    PrefNotifier::PrefStoreType store) const {
-  // Declare a temp Value* and call GetValueFromStore,
-  // ignoring the output value.
-  Value* tmp_value = NULL;
-  return GetValueFromStore(name, store, &tmp_value);
-}
-
-bool PrefValueStore::GetValueFromStore(
-    const char* name,
-    PrefNotifier::PrefStoreType store,
-    Value** out_value) const {
+bool PrefValueStore::GetValueFromStore(const char* name,
+                                       PrefValueStore::PrefStoreType store_type,
+                                       Value** out_value) const {
   // Only return true if we find a value and it is the correct type, so stale
   // values with the incorrect type will be ignored.
-  if (pref_stores_[store].get() &&
-      pref_stores_[store]->prefs()->Get(name, out_value)) {
-    // If the value is the sentinel that redirects to the default
-    // store, re-fetch the value from the default store explicitly.
-    // Because the default values are not available when creating
-    // stores, the default value must be fetched dynamically for every
-    // redirect.
+  const PrefStore* store = GetPrefStore(static_cast<PrefStoreType>(store_type));
+  if (store && store->prefs()->Get(name, out_value)) {
+    // If the value is the sentinel that redirects to the default store,
+    // re-fetch the value from the default store explicitly. Because the default
+    // values are not available when creating stores, the default value must be
+    // fetched dynamically for every redirect.
     if (PrefStore::IsUseDefaultSentinelValue(*out_value)) {
-      DCHECK(pref_stores_[PrefNotifier::DEFAULT_STORE].get());
-      if (!pref_stores_[PrefNotifier::DEFAULT_STORE]->prefs()->Get(name,
-                                                                   out_value)) {
+      store = GetPrefStore(DEFAULT_STORE);
+      if (!store || !store->prefs()->Get(name, out_value)) {
         *out_value = NULL;
         return false;
       }
-      store = PrefNotifier::DEFAULT_STORE;
+      store_type = DEFAULT_STORE;
     }
-    if (IsValidType(GetRegisteredType(name), (*out_value)->GetType(), store))
+    if (IsValidType(GetRegisteredType(name),
+                    (*out_value)->GetType(),
+                    store_type)) {
       return true;
+    }
   }
   // No valid value found for the given preference name: set the return false.
   *out_value = NULL;
   return false;
 }
 
 void PrefValueStore::RefreshPolicyPrefsOnFileThread(
     BrowserThread::ID calling_thread_id,
     PrefStore* new_managed_platform_pref_store,
     PrefStore* new_device_management_pref_store,
-    PrefStore* new_recommended_pref_store,
-    AfterRefreshCallback* callback_pointer) {
-  scoped_ptr<AfterRefreshCallback> callback(callback_pointer);
+    PrefStore* new_recommended_pref_store) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   scoped_ptr<PrefStore> managed_platform_pref_store(
       new_managed_platform_pref_store);
   scoped_ptr<PrefStore> device_management_pref_store(
       new_device_management_pref_store);
   scoped_ptr<PrefStore> recommended_pref_store(new_recommended_pref_store);
 
   PrefStore::PrefReadError read_error =
       new_managed_platform_pref_store->ReadPrefs();
   if (read_error != PrefStore::PREF_READ_ERROR_NONE) {
@@ skipping 15 matching lines @@
                << read_error;
     return;
   }
 
   BrowserThread::PostTask(
       calling_thread_id, FROM_HERE,
       NewRunnableMethod(this,
                         &PrefValueStore::RefreshPolicyPrefsCompletion,
                         managed_platform_pref_store.release(),
                         device_management_pref_store.release(),
-                        recommended_pref_store.release(),
-                        callback.release()));
+                        recommended_pref_store.release()));
+}
+
+void PrefValueStore::RefreshPolicyPrefs() {
+  using policy::ConfigurationPolicyPrefStore;
+  // Because loading of policy information must happen on the FILE
+  // thread, it's not possible to just replace the contents of the
+  // managed and recommended stores in place due to possible
+  // concurrent access from the UI thread. Instead, new stores are
+  // created and the refreshed policy read into them. The new stores
+  // are swapped with the old from a Task on the UI thread after the
+  // load is complete.
+  PrefStore* new_managed_platform_pref_store(
+      ConfigurationPolicyPrefStore::CreateManagedPlatformPolicyPrefStore());
+  PrefStore* new_device_management_pref_store(
+      ConfigurationPolicyPrefStore::CreateDeviceManagementPolicyPrefStore(
+          profile_));
+  PrefStore* new_recommended_pref_store(
+      ConfigurationPolicyPrefStore::CreateRecommendedPolicyPrefStore());
+  BrowserThread::ID current_thread_id;
+  CHECK(BrowserThread::GetCurrentThreadIdentifier(&current_thread_id));
+  BrowserThread::PostTask(
+      BrowserThread::FILE, FROM_HERE,
+      NewRunnableMethod(this,
+                        &PrefValueStore::RefreshPolicyPrefsOnFileThread,
+                        current_thread_id,
+                        new_managed_platform_pref_store,
+                        new_device_management_pref_store,
+                        new_recommended_pref_store));
 }
 
 void PrefValueStore::RefreshPolicyPrefsCompletion(
     PrefStore* new_managed_platform_pref_store,
     PrefStore* new_device_management_pref_store,
-    PrefStore* new_recommended_pref_store,
-    AfterRefreshCallback* callback_pointer) {
-  scoped_ptr<AfterRefreshCallback> callback(callback_pointer);
-
+    PrefStore* new_recommended_pref_store) {
   // Determine the paths of all the changed preferences values in the three
   // policy-related stores (managed platform, device management and
   // recommended).
   DictionaryValue* managed_platform_prefs_before(
-      pref_stores_[PrefNotifier::MANAGED_PLATFORM_STORE]->prefs());
+      GetPrefStore(MANAGED_PLATFORM_STORE)->prefs());
   DictionaryValue* managed_platform_prefs_after(
       new_managed_platform_pref_store->prefs());
   DictionaryValue* device_management_prefs_before(
-      pref_stores_[PrefNotifier::DEVICE_MANAGEMENT_STORE]->prefs());
+      GetPrefStore(DEVICE_MANAGEMENT_STORE)->prefs());
   DictionaryValue* device_management_prefs_after(
       new_device_management_pref_store->prefs());
   DictionaryValue* recommended_prefs_before(
-      pref_stores_[PrefNotifier::RECOMMENDED_STORE]->prefs());
+      GetPrefStore(RECOMMENDED_STORE)->prefs());
   DictionaryValue* recommended_prefs_after(new_recommended_pref_store->prefs());
 
   std::vector<std::string> changed_managed_platform_paths;
   managed_platform_prefs_before->GetDifferingPaths(managed_platform_prefs_after,
                                           &changed_managed_platform_paths);
 
   std::vector<std::string> changed_device_management_paths;
   device_management_prefs_before->GetDifferingPaths(
       device_management_prefs_after,
       &changed_device_management_paths);
@@ skipping 25 matching lines @@
                            changed_recommended_paths.begin(),
                            changed_recommended_paths.end(),
                            changed_paths.begin());
   changed_paths.resize(last_insert - changed_paths.begin());
 
   last_insert = unique(changed_paths.begin(), changed_paths.end());
   changed_paths.resize(last_insert - changed_paths.begin());
 
   // Replace the old stores with the new and send notification of the changed
   // preferences.
-  pref_stores_[PrefNotifier::MANAGED_PLATFORM_STORE].reset(
-      new_managed_platform_pref_store);
-  pref_stores_[PrefNotifier::DEVICE_MANAGEMENT_STORE].reset(
-      new_device_management_pref_store);
-  pref_stores_[PrefNotifier::RECOMMENDED_STORE].reset(
-      new_recommended_pref_store);
-  callback->Run(changed_paths);
+  InitPrefStore(MANAGED_PLATFORM_STORE, new_managed_platform_pref_store);
+  InitPrefStore(DEVICE_MANAGEMENT_STORE, new_device_management_pref_store);
+  InitPrefStore(RECOMMENDED_STORE, new_recommended_pref_store);
+
+  std::vector<std::string>::const_iterator current;
+  for (current = changed_paths.begin();
+       current != changed_paths.end();
+       ++current) {
+    pref_notifier_->OnPreferenceChanged(current->c_str());
+  }
 }
 
-void PrefValueStore::RefreshPolicyPrefs(
-    AfterRefreshCallback* callback) {
-  using policy::ConfigurationPolicyPrefStore;
-  // Because loading of policy information must happen on the FILE
-  // thread, it's not possible to just replace the contents of the
-  // managed and recommended stores in place due to possible
-  // concurrent access from the UI thread. Instead, new stores are
-  // created and the refreshed policy read into them. The new stores
-  // are swapped with the old from a Task on the UI thread after the
-  // load is complete.
-  PrefStore* new_managed_platform_pref_store(
-      ConfigurationPolicyPrefStore::CreateManagedPlatformPolicyPrefStore());
-  PrefStore* new_device_management_pref_store(
-      ConfigurationPolicyPrefStore::CreateDeviceManagementPolicyPrefStore(
-          profile_));
-  PrefStore* new_recommended_pref_store(
-      ConfigurationPolicyPrefStore::CreateRecommendedPolicyPrefStore());
-  BrowserThread::ID current_thread_id;
-  CHECK(BrowserThread::GetCurrentThreadIdentifier(&current_thread_id));
-  BrowserThread::PostTask(
-      BrowserThread::FILE, FROM_HERE,
-      NewRunnableMethod(this,
-                        &PrefValueStore::RefreshPolicyPrefsOnFileThread,
-                        current_thread_id,
-                        new_managed_platform_pref_store,
-                        new_device_management_pref_store,
-                        new_recommended_pref_store,
-                        callback));
+void PrefValueStore::Observe(NotificationType type,
+                             const NotificationSource& source,
+                             const NotificationDetails& details) {
+  if (type == NotificationType::POLICY_CHANGED)
+    RefreshPolicyPrefs();
 }
 
-bool PrefValueStore::HasPolicyConflictingUserProxySettings() {
-  using policy::ConfigurationPolicyPrefStore;
-  ConfigurationPolicyPrefStore::ProxyPreferenceSet proxy_prefs;
-  ConfigurationPolicyPrefStore::GetProxyPreferenceSet(&proxy_prefs);
-  ConfigurationPolicyPrefStore::ProxyPreferenceSet::const_iterator i;
-  for (i = proxy_prefs.begin(); i != proxy_prefs.end(); ++i) {
-    if ((PrefValueInManagedPlatformStore(*i) ||
-         PrefValueInDeviceManagementStore(*i)) &&
-        PrefValueInStoreRange(*i,
-                              PrefNotifier::COMMAND_LINE_STORE,
-                              PrefNotifier::USER_STORE))
-      return true;
-  }
-  return false;
+void PrefValueStore::OnPrefValueChanged(PrefValueStore::PrefStoreType type,
+                                        const std::string& key) {
+  NotifyPrefChanged(key.c_str(), type);
 }
 
-PrefStore* PrefValueStore::GetExtensionPrefStore() const {
-  return pref_stores_[PrefNotifier::EXTENSION_STORE].get();
+void PrefValueStore::OnInitializationCompleted(
+    PrefValueStore::PrefStoreType type) {
+  CheckInitializationCompleted();
 }
 
-PrefValueStore::PrefValueStore(PrefStore* managed_platform_prefs,
-                               PrefStore* device_management_prefs,
-                               PrefStore* extension_prefs,
-                               PrefStore* command_line_prefs,
-                               PrefStore* user_prefs,
-                               PrefStore* recommended_prefs,
-                               PrefStore* default_prefs,
-                               Profile* profile)
-    : profile_(profile) {
-  // NULL default pref store is usually bad, but may be OK for some unit tests.
-  if (!default_prefs)
-    LOG(WARNING) << "default pref store is null";
-  pref_stores_[PrefNotifier::MANAGED_PLATFORM_STORE].reset(
-      managed_platform_prefs);
-  pref_stores_[PrefNotifier::DEVICE_MANAGEMENT_STORE].reset(
-      device_management_prefs);
-  pref_stores_[PrefNotifier::EXTENSION_STORE].reset(extension_prefs);
-  pref_stores_[PrefNotifier::COMMAND_LINE_STORE].reset(command_line_prefs);
-  pref_stores_[PrefNotifier::USER_STORE].reset(user_prefs);
-  pref_stores_[PrefNotifier::RECOMMENDED_STORE].reset(recommended_prefs);
-  pref_stores_[PrefNotifier::DEFAULT_STORE].reset(default_prefs);
+void PrefValueStore::InitPrefStore(PrefValueStore::PrefStoreType type,
+                                   PrefStore* pref_store) {
+  pref_stores_[type].Initialize(this, pref_store, type);
 }
+
+void PrefValueStore::CheckInitializationCompleted() {
+  for (size_t i = 0; i <= PREF_STORE_TYPE_MAX; ++i) {
+    PrefStore* store = GetPrefStore(static_cast<PrefStoreType>(i));
+    if (store && !store->IsInitializationComplete())
+      return;
+  }
+  pref_notifier_->OnInitializationCompleted();
+}