Rewrite std::string("") to std::string(), Linux edition.

jingle/notifier/base/gaia_token_pre_xmpp_auth.cc

Index: jingle/notifier/base/gaia_token_pre_xmpp_auth.cc
diff --git a/jingle/notifier/base/gaia_token_pre_xmpp_auth.cc b/jingle/notifier/base/gaia_token_pre_xmpp_auth.cc
index 24aa6a9c45694ac8fafde3fcbe7251b695f54613..f7ddf8dca7b30d0e4394a7f0e304a4f3eb96643c 100644
--- a/jingle/notifier/base/gaia_token_pre_xmpp_auth.cc
+++ b/jingle/notifier/base/gaia_token_pre_xmpp_auth.cc
@@ -101,9 +101,10 @@ std::string GaiaTokenPreXmppAuth::GetAuthMechanism() const {
 
 std::string GaiaTokenPreXmppAuth::ChooseBestSaslMechanism(
     const std::vector<std::string> & mechanisms, bool encrypted) {
-  return (std::find(mechanisms.begin(),
-                    mechanisms.end(), auth_mechanism_) !=
-          mechanisms.end()) ? auth_mechanism_ : "";
+  return (std::find(mechanisms.begin(), mechanisms.end(), auth_mechanism_) !=
+              mechanisms.end())
+             ? auth_mechanism_
+             : std::string();
 }
 
 buzz::SaslMechanism* GaiaTokenPreXmppAuth::CreateSaslMechanism(