Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/gtk/gtk_theme_service.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/gtk_theme_service.h"
 
 #include <gtk/gtk.h>
 
 #include <set>
 #include <string>
@@ skipping 349 matching lines @@
 }
 
 bool GtkThemeService::UsingDefaultTheme() const {
   return !use_gtk_ && ThemeService::UsingDefaultTheme();
 }
 
 bool GtkThemeService::UsingNativeTheme() const {
   return use_gtk_;
 }
 
-void GtkThemeService::Observe(int type,
-                              const content::NotificationSource& source,
-                              const content::NotificationDetails& details) {
-  if ((type == chrome::NOTIFICATION_PREF_CHANGED) &&
-      (*content::Details<std::string>(details).ptr() ==
-          prefs::kUsesSystemTheme)) {
+void GtkThemeService::OnPreferenceChanged(PrefServiceBase* service,
+                                          const std::string& pref_name) {
+  if (pref_name == prefs::kUsesSystemTheme) {
     use_gtk_ = profile()->GetPrefs()->GetBoolean(prefs::kUsesSystemTheme);
-  } else {
-    ThemeService::Observe(type, source, details);
   }
+
+  // ThemeService does not observe prefs changes, so no need to
+  // forward to the base class.

[Mattias Nissler (ping if slow), 2012/10/31 13:29:36]

This comment does make sense for people who are aware of history, but will
confuse others. Let's just remove it.

[Jói, 2012/10/31 14:56:26]

Done.

 }
 
 GtkWidget* GtkThemeService::BuildChromeButton() {
   GtkWidget* button = HoverControllerGtk::CreateChromeButton();
   gtk_chrome_button_set_use_gtk_rendering(GTK_CHROME_BUTTON(button), use_gtk_);
   chrome_buttons_.push_back(button);
 
   signals_->Connect(button, "destroy", G_CALLBACK(OnDestroyChromeButtonThunk),
                     this);
   return button;
@@ skipping 760 matching lines @@
   cairo_new_path(cr);
   cairo_set_line_width(cr, 1.0);
   cairo_move_to(cr, start_x, allocation.y);
   cairo_line_to(cr, start_x, allocation.y + allocation.height);
   cairo_stroke(cr);
   cairo_destroy(cr);
   cairo_pattern_destroy(pattern);
 
   return TRUE;
 }