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

remoting/host/setup/daemon_controller_linux.cc

Index: remoting/host/setup/daemon_controller_linux.cc
diff --git a/remoting/host/setup/daemon_controller_linux.cc b/remoting/host/setup/daemon_controller_linux.cc
index f5076d4acbe704a40f8650eee2533f92006702e7..216572fc2e24816b588974290b7cdf9ec677c0dc 100644
--- a/remoting/host/setup/daemon_controller_linux.cc
+++ b/remoting/host/setup/daemon_controller_linux.cc
@@ -318,7 +318,7 @@ void DaemonControllerLinux::DoGetVersion(
     const GetVersionCallback& done_callback) {
   base::FilePath script_path;
   if (!GetScriptPath(&script_path)) {
-    done_callback.Run("");
+    done_callback.Run(std::string());
     return;
   }
   CommandLine command_line(script_path);
@@ -331,14 +331,14 @@ void DaemonControllerLinux::DoGetVersion(
   if (!result || exit_code != 0) {
     LOG(ERROR) << "Failed to run \"" << command_line.GetCommandLineString()
                << "\". Exit code: " << exit_code;
-    done_callback.Run("");
+    done_callback.Run(std::string());
     return;
   }
 
   TrimWhitespaceASCII(version, TRIM_ALL, &version);
   if (!ContainsOnlyChars(version, "0123456789.")) {
     LOG(ERROR) << "Received invalid host version number: " << version;
-    done_callback.Run("");
+    done_callback.Run(std::string());
     return;
   }