Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/policy/cloud_policy_refresh_scheduler.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 "chrome/browser/policy/cloud_policy_refresh_scheduler.h"
 
 #include <algorithm>
 
 #include "base/task_runner.h"
 #include "chrome/browser/policy/cloud_policy_constants.h"
@@ skipping 81 matching lines @@
   ScheduleRefresh();
 }
 
 void CloudPolicyRefreshScheduler::OnStoreError(CloudPolicyStore* store) {
   // If |store_| fails, the is_managed bit that it provides may become stale.
   // The best guess in that situation is to assume is_managed didn't change and
   // continue using the stale information. Thus, no specific response to a store
   // error is required. NB: Changes to is_managed fire OnStoreLoaded().
 }
 
-void CloudPolicyRefreshScheduler::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  DCHECK_EQ(chrome::NOTIFICATION_PREF_CHANGED, type);
-  DCHECK_EQ(refresh_delay_.GetPrefName(),
-            *content::Details<std::string>(details).ptr());
+void CloudPolicyRefreshScheduler::OnPreferenceChanged(
+    PrefServiceBase* service,
+    const std::string& pref_name) {
+  DCHECK_EQ(refresh_delay_.GetPrefName(), pref_name);
 
   ScheduleRefresh();
 }
 
 void CloudPolicyRefreshScheduler::OnIPAddressChanged() {
   if (client_->status() == DM_STATUS_REQUEST_FAILED)
     RefreshAfter(0);
 }
 
 void CloudPolicyRefreshScheduler::UpdateLastRefreshFromPolicy() {
@@ skipping 91 matching lines @@
   task_runner_->PostDelayedTask(FROM_HERE, refresh_callback_.callback(), delay);
 }
 
 int64 CloudPolicyRefreshScheduler::GetRefreshDelay() {
   return std::min(std::max<int64>(refresh_delay_.GetValue(),
                                   kRefreshDelayMinMs),
                   kRefreshDelayMaxMs);
 }
 
 }  // namespace policy