This is the second CL of several that will eventually replace TokenService with

chrome/browser/signin/signin_tracker.h

 // 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.
 
 #ifndef CHROME_BROWSER_SIGNIN_SIGNIN_TRACKER_H_
 #define CHROME_BROWSER_SIGNIN_SIGNIN_TRACKER_H_
 
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_types.h"
@@ skipping 21 matching lines @@
 // LoginUIService - Our desktop UI flows rely on having only a single login flow
 // visible to the user at once. This is achieved via LoginUIService
 // (a BrowserContextKeyedService that keeps track of the currently visible
 // login UI).
 //
 // SigninManager - Records the currently-logged-in user and handles all
 // interaction with the GAIA backend during the signin process. Unlike
 // SigninTracker, SigninManager only knows about the GAIA login state and is
 // not aware of the state of any signed in services.
 //
-// TokenService - Uses credentials provided by SigninManager to generate tokens
-// for all signed-in services in Chrome.
-//
 // OAuth2TokenService - Maintains and manages OAuth2 tokens for the accounts
 // connected to this profile.
 //
 // ProfileSyncService - Provides the external API for interacting with the
-// sync framework. Listens for notifications from the TokenService to know
-// when to startup sync, and provides an Observer interface to notify the UI
-// layer of changes in sync state so they can be reflected in the UI.
+// sync framework. Listens for notifications for tokens to know when to startup
+// sync, and provides an Observer interface to notify the UI layer of changes
+// in sync state so they can be reflected in the UI.
 class SigninTracker : public content::NotificationObserver,
                       public OAuth2TokenService::Observer {
  public:
   class Observer {
    public:
     // The signin attempt failed, and the cause is passed in |error|.
     virtual void SigninFailed(const GoogleServiceAuthError& error) = 0;
 
     // The signin attempt succeeded.
     virtual void SigninSuccess() = 0;
@@ skipping 24 matching lines @@
   // Weak pointer to the observer we call when the signin state changes.
   Observer* observer_;
 
   // Used to listen to notifications from the SigninManager.
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(SigninTracker);
 };
 
 #endif  // CHROME_BROWSER_SIGNIN_SIGNIN_TRACKER_H_