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

dbus/message.cc

Index: dbus/message.cc
diff --git a/dbus/message.cc b/dbus/message.cc
index ce53a485375fdcbe07400c3841e35e0cdf5c66b2..737b0c494bfe3f449abc230844a51268117778cf 100644
--- a/dbus/message.cc
+++ b/dbus/message.cc
@@ -87,7 +87,7 @@ std::string Message::GetMessageTypeAsString() {
       return "MESSAGE_ERROR";
   }
   NOTREACHED();
-  return "";
+  return std::string();
 }
 
 std::string Message::ToStringInternal(const std::string& indent,
@@ -251,7 +251,7 @@ std::string Message::ToStringInternal(const std::string& indent,
 // ...
 std::string Message::ToString() {
   if (!raw_message_)
-    return "";
+    return std::string();
 
   // Generate headers first.
   std::string headers;
@@ -268,7 +268,7 @@ std::string Message::ToString() {
 
   // Generate the payload.
   MessageReader reader(this);
-  return headers + "\n" + ToStringInternal("", &reader);
+  return headers + "\n" + ToStringInternal(std::string(), &reader);
 }
 
 bool Message::SetDestination(const std::string& destination) {