Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/gtk/browser_toolbar_gtk.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/ui/gtk/browser_toolbar_gtk.h"
 
 #include <gdk/gdkkeysyms.h>
 #include <gtk/gtk.h>
 #include <X11/XF86keysym.h>
 
@@ skipping 350 matching lines @@
   if (accelerator_gtk)
     *accelerator = *accelerator_gtk;
   return !!accelerator_gtk;
 }
 
 // content::NotificationObserver -----------------------------------------------
 
 void BrowserToolbarGtk::Observe(int type,
                                 const content::NotificationSource& source,
                                 const content::NotificationDetails& details) {
-  if (type == chrome::NOTIFICATION_PREF_CHANGED) {
-    NotifyPrefChanged(content::Details<std::string>(details).ptr());
-  } else if (type == chrome::NOTIFICATION_BROWSER_THEME_CHANGED) {
+  if (type == chrome::NOTIFICATION_BROWSER_THEME_CHANGED) {
     // Update the spacing around the menu buttons
     bool use_gtk = theme_service_->UsingNativeTheme();
     int border = use_gtk ? 0 : 2;
     gtk_container_set_border_width(
         GTK_CONTAINER(wrench_menu_button_->widget()), border);
 
     // Force the height of the toolbar so we get the right amount of padding
     // above and below the location bar. We always force the size of the widgets
     // to either side of the location box, but we only force the location box
     // size in chrome-theme mode because that's the only time we try to control
@@ skipping 35 matching lines @@
     wrench_menu_model_->UpdateZoomControls();
 
     // If our zoom level changed, we need to tell the menu to update its state,
     // since the menu could still be open.
     wrench_menu_->UpdateMenu();
   } else {
     NOTREACHED();
   }
 }
 
+void BrowserToolbarGtk::OnPreferenceChanged(PrefServiceBase* service,
+                                            const std::string& pref_name) {
+  NotifyPrefChanged(pref_name);
+}
+
 // BrowserToolbarGtk, public ---------------------------------------------------
 
 void BrowserToolbarGtk::UpdateWebContents(WebContents* contents,
                                           bool should_restore_state) {
   location_bar_->Update(should_restore_state ? contents : NULL);
 
   if (actions_toolbar_.get())
     actions_toolbar_->Update();
 }
 
@@ skipping 204 matching lines @@
   if (!url.is_valid())
     return;
 
   bool url_is_newtab = url.SchemeIs(chrome::kChromeUIScheme) &&
                        url.host() == chrome::kChromeUINewTabHost;
   home_page_is_new_tab_page_.SetValue(url_is_newtab);
   if (!url_is_newtab)
     home_page_.SetValue(url.spec());
 }
 
-void BrowserToolbarGtk::NotifyPrefChanged(const std::string* pref) {
-  if (!pref || *pref == prefs::kShowHomeButton) {
+void BrowserToolbarGtk::NotifyPrefChanged(const std::string& pref) {
+  if (pref == prefs::kShowHomeButton) {
     bool visible = show_home_button_.GetValue() && !ShouldOnlyShowLocation();
     gtk_widget_set_visible(home_->widget(), visible);
   }
 
-  if (!pref ||
-      *pref == prefs::kHomePage ||
-      *pref == prefs::kHomePageIsNewTabPage)
+  if (pref == prefs::kHomePage ||
+      pref == prefs::kHomePageIsNewTabPage)
     SetUpDragForHomeButton(!home_page_.IsManaged() &&
                            !home_page_is_new_tab_page_.IsManaged());
 }
 
 bool BrowserToolbarGtk::ShouldOnlyShowLocation() const {
   // If we're a popup window, only show the location bar (omnibox).
   return !browser_->is_type_tabbed();
 }
 
 void BrowserToolbarGtk::RebuildWrenchMenu() {
@@ skipping 26 matching lines @@
   const gfx::ImageSkia* badge = theme_service_->GetImageSkiaNamed(resource_id);
   gfx::CanvasSkiaPaint canvas(expose, false);
   int x_offset = base::i18n::IsRTL() ? 0 : allocation.width - badge->width();
   int y_offset = 0;
   canvas.DrawImageInt(*badge,
                       allocation.x + x_offset,
                       allocation.y + y_offset);
 
   return FALSE;
 }