chrome.exe --user-agent="Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0)" google chromeでこうすればできるよ
"C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Chrome\Application\chrome.exe" --user-agent="Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)"