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

media/crypto/aes_decryptor.cc

Index: media/crypto/aes_decryptor.cc
diff --git a/media/crypto/aes_decryptor.cc b/media/crypto/aes_decryptor.cc
index e214b06852833b96ad985c53d7f0a107c895f3c9..430568cbaea30a2ed9f8c4ba61680a70fee0d950 100644
--- a/media/crypto/aes_decryptor.cc
+++ b/media/crypto/aes_decryptor.cc
@@ -152,7 +152,7 @@ bool AesDecryptor::GenerateKeyRequest(const std::string& key_system,
                           init_data_length);
   }
 
-  key_message_cb_.Run(key_system, session_id_string, message, "");
+  key_message_cb_.Run(key_system, session_id_string, message, std::string());
   return true;
 }