Let Ubertoken Fetch be primed with an access token.

google_apis/gaia/ubertoken_fetcher.cc

Index: google_apis/gaia/ubertoken_fetcher.cc
diff --git a/google_apis/gaia/ubertoken_fetcher.cc b/google_apis/gaia/ubertoken_fetcher.cc
index 15e5932bed620498fe8ede7fc2cd6ad2369c987d..6cfe15f1bba00505878e57923efff8e3610d1c55 100644
--- a/google_apis/gaia/ubertoken_fetcher.cc
+++ b/google_apis/gaia/ubertoken_fetcher.cc
@@ -43,6 +43,16 @@ void UbertokenFetcher::StartFetchingToken(const std::string& account_id) {
   RequestAccessToken();
 }
 
+void UbertokenFetcher::StartFetchingTokenWithAccessToken(
+    const std::string& account_id, const std::string& access_token) {
+  DCHECK(!account_id.empty());
+  DCHECK(!access_token.empty());
+
+  account_id_ = account_id;
+  access_token_ = access_token;
+  ExchangeTokens();
+}
+
 void UbertokenFetcher::OnUberAuthTokenSuccess(const std::string& token) {
   consumer_->OnUbertokenSuccess(token);
 }