SigninManager owns ObserverList for the MergeSessionHelper.

components/signin/core/browser/signin_manager.h

 // Copyright 2014 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.
 //
 // The signin manager encapsulates some functionality tracking
 // which user is signed in. See SigninManagerBase for full description of
 // responsibilities. The class defined in this file provides functionality
 // required by all platforms except Chrome OS.
 //
 // When a user is signed in, a ClientLogin request is run on their behalf.
@@ skipping 28 matching lines @@
 #include "google_apis/gaia/google_service_auth_error.h"
 #include "google_apis/gaia/merge_session_helper.h"
 #include "net/cookies/canonical_cookie.h"
 
 class PrefService;
 class ProfileOAuth2TokenService;
 class SigninAccountIdHelper;
 class SigninClient;
 
 class SigninManager : public SigninManagerBase,
-                      public AccountTrackerService::Observer {
+                      public AccountTrackerService::Observer,
+                      public MergeSessionHelper::Observer {
  public:
   // The callback invoked once the OAuth token has been fetched during signin,
   // but before the profile transitions to the "signed-in" state. This allows
   // callers to load policy and prompt the user appropriately before completing
   // signin. The callback is passed the just-fetched OAuth login refresh token.
   typedef base::Callback<void(const std::string&)> OAuthTokenFetchedCallback;
 
   // Returns true if |url| is a web signin URL and should be hosted in an
   // isolated, privileged signin process.
   static bool IsWebBasedSigninFlowURL(const GURL& url);
@@ skipping 111 matching lines @@
 
   // Waits for the AccountTrackerService, then sends GoogleSigninSucceeded to
   // the client and clears the local password.
   void PostSignedIn();
 
   // AccountTrackerService::Observer implementation.
   void OnAccountUpdated(const AccountTrackerService::AccountInfo& info)
       override;
   void OnAccountUpdateFailed(const std::string& account_id) override;
 
+  // MergeSessionHelper::Observer implementation. SigninManager controls the
+  // lifetime if the MergeSessionHelper, so SigninManager takes responsibility
+  // for propogating these notifications.
+  void MergeSessionCompleted(const std::string& account_id,
+                             const GoogleServiceAuthError& error) override;
+  void GetCheckConnectionInfoCompleted(bool succeeded) override;
+
   // Called when a new request to re-authenticate a user is in progress.
   // Will clear in memory data but leaves the db as such so when the browser
   // restarts we can use the old token(which might throw a password error).
   void ClearTransientSigninData();
 
   // Called to handle an error from a GAIA auth fetch.  Sets the last error
   // to |error|, sends out a notification of login failure and clears the
   // transient signin data.
   void HandleAuthError(const GoogleServiceAuthError& error);
 
@@ skipping 31 matching lines @@
   // Helper object to listen for changes to signin preferences stored in non-
   // profile-specific local prefs (like kGoogleServicesUsernamePattern).
   PrefChangeRegistrar local_state_pref_registrar_;
 
   // Helper object to listen for changes to the signin allowed preference.
   BooleanPrefMember signin_allowed_;
 
   // Helper to merge signed in account into the content area.
   scoped_ptr<MergeSessionHelper> merge_session_helper_;
 
+  // Observers of the |merge_session_helper_| across reset()s.
+  ObserverList<MergeSessionHelper::Observer, true> merge_session_observer_list_;
+
   // Two gate conditions for when PostSignedIn should be called. Verify
   // that the SigninManager has reached OnSignedIn() and the AccountTracker
   // has completed calling GetUserInfo.
   bool signin_manager_signed_in_;
   bool user_info_fetched_by_account_tracker_;
 
   base::WeakPtrFactory<SigninManager> weak_pointer_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SigninManager);
 };
 
 #endif  // !defined(OS_CHROMEOS)
 
 #endif  // COMPONENTS_SIGNIN_CORE_BROWSER_SIGNIN_MANAGER_H_