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

components/signin/core/browser/signin_manager.cc

Index: components/signin/core/browser/signin_manager.cc
diff --git a/components/signin/core/browser/signin_manager.cc b/components/signin/core/browser/signin_manager.cc
index 7856c7855e2414a94fd158f0e901492a60e7c058..5ced320782343e23fffd226d792388bd95516fd4 100644
--- a/components/signin/core/browser/signin_manager.cc
+++ b/components/signin/core/browser/signin_manager.cc
@@ -54,6 +54,8 @@ std::string SigninManager::SigninTypeToString(SigninManager::SigninType type) {
       return "No Signin";
     case SIGNIN_TYPE_WITH_REFRESH_TOKEN:
       return "With refresh token";
+    case SIGNIN_TYPE_WITHOUT_REFRESH_TOKEN:
+      return "Without refresh token";
   }
 
   NOTREACHED();
@@ -101,19 +103,21 @@ void SigninManager::StartSignInWithRefreshToken(
     const std::string& password,
     const OAuthTokenFetchedCallback& callback) {
   DCHECK(!IsAuthenticated());
-
-  if (!PrepareForSignin(SIGNIN_TYPE_WITH_REFRESH_TOKEN, gaia_id, username,
-                        password)) {
+  SigninType signin_type = refresh_token.empty()
+                               ? SIGNIN_TYPE_WITHOUT_REFRESH_TOKEN
+                               : SIGNIN_TYPE_WITH_REFRESH_TOKEN;
+  if (!PrepareForSignin(signin_type, gaia_id, username, password)) {
     return;
   }
 
-  // Store our token.
+  // Store the refresh token.
   temp_refresh_token_ = refresh_token;
 
-  if (!callback.is_null() && !temp_refresh_token_.empty()) {
+  if (!callback.is_null()) {
+    // Callback present, let the caller complete the pending sign-in.
     callback.Run(temp_refresh_token_);
   } else {
-    // No oauth token or callback, so just complete our pending signin.
+    // No callback, so just complete the pending signin.
     CompletePendingSignin();
   }
 }
@@ -350,13 +354,13 @@ void SigninManager::CompletePendingSignin() {
   DCHECK(!possibly_invalid_account_id_.empty());
   OnSignedIn();
 
-  DCHECK(!temp_refresh_token_.empty());
   DCHECK(IsAuthenticated());
 
-  std::string account_id = GetAuthenticatedAccountId();
-  token_service_->UpdateCredentials(account_id, temp_refresh_token_);
-  temp_refresh_token_.clear();
-
+  if (!temp_refresh_token_.empty()) {
+    std::string account_id = GetAuthenticatedAccountId();
+    token_service_->UpdateCredentials(account_id, temp_refresh_token_);
+    temp_refresh_token_.clear();
+  }
   MergeSigninCredentialIntoCookieJar();
 }