Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/views/tabs/browser_tab_strip_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/views/tabs/browser_tab_strip_controller.h"
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/tab_helper.h"
@@ skipping 484 matching lines @@
                              GetActiveIndex();
   if (index == -1)
     return;
   SetTabDataAt(web_contents ? web_contents :
       chrome::GetWebContentsAt(browser_, index), index);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // BrowserTabStripController, content::NotificationObserver implementation:
 
-void BrowserTabStripController::Observe(int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  switch (type) {
-    case chrome::NOTIFICATION_PREF_CHANGED:
-      if (*content::Details<std::string>(details).ptr() ==
-          prefs::kTabStripLayoutType) {
-        UpdateLayoutType();
-      }
-      break;
-
-    default:
-      NOTREACHED();
-      break;
+void BrowserTabStripController::OnPreferenceChanged(
+    PrefServiceBase* service,
+    const std::string& pref_name) {
+  if (pref_name == prefs::kTabStripLayoutType) {
+    UpdateLayoutType();
   }
 }
 
 void BrowserTabStripController::SetTabRendererDataFromModel(
     WebContents* contents,
     int model_index,
     TabRendererData* data,
     TabStatus tab_status) {
   FaviconTabHelper* favicon_tab_helper =
       FaviconTabHelper::FromWebContents(contents);
@@ skipping 65 matching lines @@
   SetTabRendererDataFromModel(contents->web_contents(), index, &data, NEW_TAB);
   tabstrip_->AddTabAt(index, data, is_active);
 }
 
 void BrowserTabStripController::UpdateLayoutType() {
   bool adjust_layout = false;
   TabStripLayoutType layout_type =
       DetermineTabStripLayout(g_browser_process->local_state(), &adjust_layout);
   tabstrip_->SetLayoutType(layout_type, adjust_layout);
 }