Don't use $USER for Local Login check

remoting/base/util.h

Index: remoting/base/util.h
diff --git a/remoting/base/util.h b/remoting/base/util.h
index e6abe0fa98c54441170e8582e8586e8b9fe620b2..8f70005b8dc5fd3fe124a2c9f07881f1d76e3ff4 100644
--- a/remoting/base/util.h
+++ b/remoting/base/util.h
@@ -92,6 +92,10 @@ std::string ReplaceCrLfByLf(const std::string& in);
 // Checks if the given string is a valid UTF-8 string.
 bool StringIsUtf8(const char* data, size_t length);
 
+// Returns the username associated with this process, or the empty string on
+// error or if not implemented.
+std::string GetUsername();
+
 }  // namespace remoting
 
 #endif  // REMOTING_BASE_UTIL_H_