Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/captive_portal/captive_portal_service.h

Index: chrome/browser/captive_portal/captive_portal_service.h
diff --git a/chrome/browser/captive_portal/captive_portal_service.h b/chrome/browser/captive_portal/captive_portal_service.h
index 82b3d7171d91a2240b5577f7f983a4472f263505..35badc474efc4127dec11560cd7f7a84c0ddbe14 100644
--- a/chrome/browser/captive_portal/captive_portal_service.h
+++ b/chrome/browser/captive_portal/captive_portal_service.h
@@ -7,13 +7,13 @@
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/prefs/public/pref_observer.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/time.h"
 #include "base/timer.h"
 #include "chrome/browser/api/prefs/pref_member.h"
 #include "chrome/browser/captive_portal/captive_portal_detector.h"
 #include "chrome/browser/profiles/profile_keyed_service.h"
-#include "content/public/browser/notification_observer.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/backoff_entry.h"
 
@@ -29,7 +29,7 @@ namespace captive_portal {
 // be accessed on the UI thread.
 // Design doc: https://docs.google.com/document/d/1k-gP2sswzYNvryu9NcgN7q5XrsMlUdlUdoW9WRaEmfM/edit
 class CaptivePortalService : public ProfileKeyedService,
-                             public content::NotificationObserver,
+                             public PrefObserver,
                              public base::NonThreadSafe {
  public:
   enum TestingState {
@@ -116,11 +116,9 @@ class CaptivePortalService : public ProfileKeyedService,
   void OnPortalDetectionCompleted(
       const CaptivePortalDetector::Results& results);
 
-  // content::NotificationObserver:
-  virtual void Observe(
-      int type,
-      const content::NotificationSource& source,
-      const content::NotificationDetails& details) OVERRIDE;
+  // PrefObserver
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
 
   // ProfileKeyedService:
   virtual void Shutdown() OVERRIDE;