nsLocalFile::Launch, where we have a code to handle
SE_ERR_* errors, but those errors are not returned as a return value but returned as
SHELLEXECUTEINFO::hInstApp. Moreover, we pass
ShellExecuteExW to execute a file asyncronously. In such a case,
ShellExecuteExW will not return API
SE_ERR_NOASSOC though a target file does not have an associated app.
As a fix for Bug 1588975, we replace
IShellDispatch2.ShellExecute which is also asynchronous. We can simply return either
NS_ERROR_FILE_EXECUTION_FAILED as we do in nsMIMEInfoWin.cpp, removing these error handling code.