Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/printing/print_view_manager.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/printing/print_view_manager.h"
 
 #include <map>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 371 matching lines @@
 }
 
 void PrintViewManager::Observe(int type,
                                const content::NotificationSource& source,
                                const content::NotificationDetails& details) {
   switch (type) {
     case chrome::NOTIFICATION_PRINT_JOB_EVENT: {
       OnNotifyPrintJobEvent(*content::Details<JobEventDetails>(details).ptr());
       break;
     }
-    case chrome::NOTIFICATION_PREF_CHANGED: {
-      UpdateScriptedPrintingBlocked();
-      break;
-    }
     case chrome::NOTIFICATION_CONTENT_BLOCKED_STATE_CHANGED: {
       tab_content_blocked_ = *content::Details<const bool>(details).ptr();
       UpdateScriptedPrintingBlocked();
       break;
     }
     default: {
       NOTREACHED();
       break;
     }
   }
 }
 
+void PrintViewManager::OnPreferenceChanged(PrefServiceBase* service,
+                                           const std::string& pref_name) {
+  UpdateScriptedPrintingBlocked();
+}
+
 void PrintViewManager::OnNotifyPrintJobEvent(
     const JobEventDetails& event_details) {
   switch (event_details.type()) {
     case JobEventDetails::FAILED: {
       TerminatePrintJob(true);
 
       content::NotificationService::current()->Notify(
           chrome::NOTIFICATION_PRINT_JOB_RELEASED,
           content::Source<content::WebContents>(web_contents()),
           content::NotificationService::NoDetails());
@@ skipping 265 matching lines @@
   scoped_refptr<printing::PrinterQuery> printer_query;
   print_job_manager->PopPrinterQuery(cookie, &printer_query);
   if (!printer_query.get())
     return;
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&PrinterQuery::StopWorker, printer_query.get()));
 }
 
 }  // namespace printing