Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/gtk/browser_toolbar_gtk.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_UI_GTK_BROWSER_TOOLBAR_GTK_H_
 #define CHROME_BROWSER_UI_GTK_BROWSER_TOOLBAR_GTK_H_
 
 #include <gtk/gtk.h>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/prefs/public/pref_observer.h"
 #include "chrome/browser/api/prefs/pref_member.h"
 #include "chrome/browser/command_observer.h"
 #include "chrome/browser/ui/gtk/custom_button.h"
 #include "chrome/browser/ui/gtk/menu_gtk.h"
 #include "chrome/browser/ui/toolbar/wrench_menu_model.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "ui/base/accelerators/accelerator.h"
 #include "ui/base/gtk/gtk_signal.h"
 #include "ui/base/gtk/gtk_signal_registrar.h"
@@ skipping 13 matching lines @@
 
 namespace content {
 class WebContents;
 }
 
 // View class that displays the GTK version of the toolbar and routes gtk
 // events back to the Browser.
 class BrowserToolbarGtk : public CommandObserver,
                           public ui::AcceleratorProvider,
                           public MenuGtk::Delegate,
-                          public content::NotificationObserver {
+                          public content::NotificationObserver,
+                          public PrefObserver {
  public:
   BrowserToolbarGtk(Browser* browser, BrowserWindowGtk* window);
   virtual ~BrowserToolbarGtk();
 
   // Create the contents of the toolbar. |top_level_window| is the GtkWindow
   // to which we attach our accelerators.
   void Init(GtkWindow* top_level_window);
 
   // Set the various widgets' ViewIDs.
   void SetViewIDs();
@@ skipping 40 matching lines @@
   // Overridden from ui::AcceleratorProvider:
   virtual bool GetAcceleratorForCommandId(
       int id,
       ui::Accelerator* accelerator) OVERRIDE;
 
   // content::NotificationObserver implementation.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
+  // PrefObserver implementation.
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
+
   // Whether the wrench/hotdogs menu is currently visible to the user.
   bool IsWrenchMenuShowing() const;
 
   // Message that we should react to a state change.
   void UpdateWebContents(content::WebContents* contents,
                          bool should_restore_state);
 
  private:
   // Connect/Disconnect signals for dragging a url onto the home button.
   void SetUpDragForHomeButton(bool enable);
@@ skipping 19 matching lines @@
 
   // Used for drags onto home button.
   CHROMEGTK_CALLBACK_6(BrowserToolbarGtk, void, OnDragDataReceived,
                        GdkDragContext*, gint, gint, GtkSelectionData*,
                        guint, guint);
 
   // Used to draw the upgrade notification badge.
   CHROMEGTK_CALLBACK_1(BrowserToolbarGtk, gboolean, OnWrenchMenuButtonExpose,
                        GdkEventExpose*);
 
-  // Updates preference-dependent state.
+  // Updates preference-dependent state. |pref| may be NULL.
   void NotifyPrefChanged(const std::string* pref);
 
   static void SetSyncMenuLabel(GtkWidget* widget, gpointer userdata);
 
   // Sometimes we only want to show the location w/o the toolbar buttons (e.g.,
   // in a popup window).
   bool ShouldOnlyShowLocation() const;
 
   // Rebuilds the wrench menu.
   void RebuildWrenchMenu();
@@ skipping 61 matching lines @@
   // rendering.
   ui::OwnedWidgetGtk offscreen_entry_;
 
   // Manages the home button drop signal handler.
   scoped_ptr<ui::GtkSignalRegistrar> drop_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserToolbarGtk);
 };
 
 #endif  // CHROME_BROWSER_UI_GTK_BROWSER_TOOLBAR_GTK_H_