Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/browser_instant_controller.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/browser_instant_controller.h"
 
 #include "chrome/browser/browser_shutdown.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/instant/instant_controller.h"
 #include "chrome/browser/prefs/pref_service.h"
@@ skipping 86 matching lines @@
   // NOTE: This is only invoked on aura.
   browser_->window()->WebContentsFocused(
       instant_->GetPreviewContents()->web_contents());
 }
 
 TabContents* BrowserInstantController::GetActiveTabContents() const {
   return chrome::GetActiveTabContents(browser_);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-// BrowserInstantController, content::NotificationObserver implementation:
+// BrowserInstantController, PrefObserver implementation:
 
-void BrowserInstantController::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  DCHECK_EQ(chrome::NOTIFICATION_PREF_CHANGED, type);
-  DCHECK_EQ(std::string(prefs::kInstantEnabled),
-            *content::Details<std::string>(details).ptr());
+void BrowserInstantController::OnPreferenceChanged(
+    PrefServiceBase* service,
+    const std::string& pref_name) {
+  DCHECK_EQ(std::string(prefs::kInstantEnabled), pref_name);
   ResetInstant();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // BrowserInstantController, TabStripModelObserver implementation:
 
 void BrowserInstantController::TabDeactivated(TabContents* contents) {
   if (instant())
     instant_->Hide();
 }
@@ skipping 17 matching lines @@
           InstantController::CreateInstant(browser_->profile(), this) : NULL);
 
   // Notify any observers that they need to reset.
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_BROWSER_INSTANT_RESET,
       content::Source<BrowserInstantController>(this),
       content::NotificationService::NoDetails());
 }
 
 }  // namespace chrome