The Google Chrome for iOS acquires a new function confidentiality which allows them users to lock open Incognito tabs and unlock them with Face ID or Touch ID of iPhone their.

Users usually use the Incognito feature when visiting sites that do not want to appear in its history browser their. However, if one user does not lock it phone , one could log in to Chrome and view the currently open anonymous browsing tabs.
So, to offer extra protection, the Chrome Beta for iOS tries a new feature set prevents the browser from displaying Incognito tabs unless they are first unlocked with Face ID.
"You can add more safety at Incognito Tabs with Touch ID or Face ID. When you return to the application Chrome, the tabs anonymous browsing will be blurred until you confirm that it is youSays Google Chrome Beta.
Therefore, if you have closed Chrome for iOS and try to open it later, you should follow the procedure above.

How to enable the ability to lock Incognito tabs in Chrome for iOS?
First of all, you should keep in mind that when installing Chrome Beta, you will change the existing installation of Chrome in device you.
To enable the lock feature, follow these steps:
- Install it Apple's TestFlight iOS app on your iPhone or iPad
- On the same device, visit TestFlight invitation URL for Chrome Beta for iOS
- When it opens TestFlight, accept the license and install Chrome Beta (if a message appears saying Beta is complete, you will have to wait until a new invitation is available Chrome Beta Google).
- When it is installed Chrome Beta for iOS 89, type chrome: // flags in the address bar, then look for “Device authentication for anonymous browsing“. When the flag appears, set it to "On".
- Now close and reopen the Chrome browser for iOS.
- When Chrome reopens, go to Settings> Privacy and enable the “Lock Incognito tabs when Chrome closes".

If you follow the above procedure, then the next time you open the browser on Incognito tabs, you will be asked to unlock them with Face ID or Touch ID.
If you want to turn off this feature, just go back to chrome: // flags and turn off the setting.
Source: Bleeping Computer