Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/printing/print_view_manager.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.
 
 #ifndef CHROME_BROWSER_PRINTING_PRINT_VIEW_MANAGER_H_
 #define CHROME_BROWSER_PRINTING_PRINT_VIEW_MANAGER_H_
 
 #include "base/memory/ref_counted.h"
+#include "base/prefs/public/pref_observer.h"
 #include "base/string16.h"
 #include "chrome/browser/api/prefs/pref_member.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 #include "printing/printed_pages_source.h"
 
 struct PrintHostMsg_DidPrintPage_Params;
 
 namespace content {
 class RenderProcessHost;
 class RenderViewHost;
 }
 
 namespace printing {
 
 class JobEventDetails;
 class PrintJob;
 class PrintJobWorkerOwner;
 class PrintViewManagerObserver;
 
 // Manages the print commands for a WebContents.
 class PrintViewManager : public content::NotificationObserver,
+                         public PrefObserver,
                          public PrintedPagesSource,
                          public content::WebContentsObserver,
                          public content::WebContentsUserData<PrintViewManager> {
  public:
   virtual ~PrintViewManager();
 
   // Prints the current document immediately. Since the rendering is
   // asynchronous, the actual printing will not be completed on the return of
   // this function. Returns false if printing is impossible at the moment.
   bool PrintNow();
@@ skipping 27 matching lines @@
   void PrintPreviewDone();
 
   // Whether to block scripted printing for our tab or not.
   void UpdateScriptedPrintingBlocked();
 
   // Sets |observer| as the current PrintViewManagerObserver. Pass in NULL to
   // remove the current observer. |observer| may always be NULL, but |observer_|
   // must be NULL if |observer| is non-NULL.
   void set_observer(PrintViewManagerObserver* observer);
 
+  // PrefObserver implementation.
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
+
   // PrintedPagesSource implementation.
   virtual string16 RenderSourceName() OVERRIDE;
 
   // content::NotificationObserver implementation.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
   // content::WebContentsObserver implementation.
   virtual void DidStartLoading(
@@ skipping 122 matching lines @@
 
   // Whether our content is in blocked state.
   bool tab_content_blocked_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintViewManager);
 };
 
 }  // namespace printing
 
 #endif  // CHROME_BROWSER_PRINTING_PRINT_VIEW_MANAGER_H_