question: public static ExternalAppId determineExternalIntentSource ( String packageName , Intent intent ) { String appId = IntentUtils . safeGetStringExtra ( intent , Browser . EXTRA_APPLICATION_ID ) ; ExternalAppId externalId = ExternalAppId . OTHER ; if ( appId == null ) { String url = getUrlFromIntent ( intent ) ; if ( url != null && url . startsWith ( TWITTER_LINK_PREFIX ) ) { externalId = ExternalAppId . TWITTER ; } else if ( url != null && url . startsWith ( FACEBOOK_LINK_PREFIX ) ) { externalId = ExternalAppId . FACEBOOK ; } else if ( url != null && url . startsWith ( NEWS_LINK_PREFIX ) ) { externalId = ExternalAppId . NEWS ; } } else { if ( appId . equals ( PACKAGE_PLUS ) ) { externalId = ExternalAppId . PLUS ; } else if ( appId . equals ( PACKAGE_GMAIL ) ) { externalId = ExternalAppId . GMAIL ; } else if ( appId . equals ( PACKAGE_HANGOUTS ) ) { externalId = ExternalAppId . HANGOUTS ; } else if ( appId . equals ( PACKAGE_MESSENGER ) ) { externalId = ExternalAppId . MESSENGER ; } else if ( appId . equals ( PACKAGE_LINE ) ) { externalId = ExternalAppId . LINE ; } else if ( appId . equals ( PACKAGE_WHATSAPP ) ) { externalId = ExternalAppId . WHATSAPP ; } else if ( appId . equals ( PACKAGE_GSA ) ) { externalId = ExternalAppId . GSA ; } else if ( appId . equals ( packageName ) ) { externalId = ExternalAppId . CHROME ; } } return externalId ; }
target:  Determines what App was used to fire this Intent.