am be3770f3: am b68162a9: cherrypick Change-Id: I60c74919ab3df359f47e5052bcc1469318a5b821 add notice about large screen devices and the "mobile" string in user agent

* commit 'be3770f3f932c5242e387b5dbc8baa75fb3bf373':
  cherrypick Change-Id: I60c74919ab3df359f47e5052bcc1469318a5b821 add notice about large screen devices and the "mobile" string in user agent