[DICE] Enable sync for an account that is already present in the token service.

components/signin/core/browser/signin_manager.h

Index: components/signin/core/browser/signin_manager.h
diff --git a/components/signin/core/browser/signin_manager.h b/components/signin/core/browser/signin_manager.h
index 92e9ff587eca25c491ee14f326b9db83e7b2f22f..bae32cf78e4123fe6d9546e15b13585faf5fdb6f 100644
--- a/components/signin/core/browser/signin_manager.h
+++ b/components/signin/core/browser/signin_manager.h
@@ -74,8 +74,10 @@ class SigninManager : public SigninManagerBase,
                                         const std::string& policy);
 
   // Attempt to sign in this user with a refresh token.
+  // If |refresh_token| is not empty, then SigninManager will add it to the
+  // |token_service_| when the sign-in flow is completed.
   // If non-null, the passed |oauth_fetched_callback| callback is invoked once
-  // signin has been completed.
+  // sign-in has been completed.
   // The callback should invoke SignOut() or CompletePendingSignin() to either
   // continue or cancel the in-process signin.
   virtual void StartSignInWithRefreshToken(
@@ -152,7 +154,11 @@ class SigninManager : public SigninManagerBase,
                          signin_metrics::SignoutDelete signout_delete_metric);
 
  private:
-  enum SigninType { SIGNIN_TYPE_NONE, SIGNIN_TYPE_WITH_REFRESH_TOKEN };
+  enum SigninType {
+    SIGNIN_TYPE_NONE,
+    SIGNIN_TYPE_WITH_REFRESH_TOKEN,
+    SIGNIN_TYPE_WITHOUT_REFRESH_TOKEN
+  };
 
   std::string SigninTypeToString(SigninType type);
   friend class FakeSigninManager;