Update strings.js
check chrome version before using getAllStyleSheets API
initialize _userAgent
Merge pull request #7717 from adobe/alf_localization

ALF Automation
regex improvement
get user agent earlier
Merge pull request #7712 from adobe/randy/issue-7127

Check Chrome version before using CSS.getAllStyleSheets() API
Merge pull request #7710 from diomed/patch-3

Update strings.js
Updated by ALF automation.