[Sync] Try to fix race conditions in CookieJarMismatch.

components/browser_sync/profile_sync_service.h

Index: components/browser_sync/profile_sync_service.h
diff --git a/components/browser_sync/profile_sync_service.h b/components/browser_sync/profile_sync_service.h
index b409a3e9e5e3e6ca07cc5ef8d8a48b3e6d25421e..88837d3b6edead6a6181b89bd5dbeefc5d2164af 100644
--- a/components/browser_sync/profile_sync_service.h
+++ b/components/browser_sync/profile_sync_service.h
@@ -395,6 +395,13 @@ class ProfileSyncService : public syncer::SyncServiceBase,
       const std::vector<gaia::ListedAccount>& signed_out_accounts,
       const GoogleServiceAuthError& error) override;
 
+  // Similar to above but with a callback that will be invoked on completion.
+  void OnGaiaAccountsInCookieUpdatedWithCallback(
+      const std::vector<gaia::ListedAccount>& accounts,
+      const std::vector<gaia::ListedAccount>& signed_out_accounts,
+      const GoogleServiceAuthError& error,
+      const base::Closure& callback);
+
   // Get the sync status code.
   SyncStatusSummary QuerySyncStatusSummary();