UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36

Steps to reproduce the problem:
Hi.
We are looking to add programmatically (script / API) an URL to the existing start pages of the current Google chrome.
Let's take an example. 
We have 2 start pages (Gmail and Yahoo Mail) that are automatically loaded when we start Google Chrome.
We are looking to add an URL to the start pages e.g. we will have 3 pages that open automatically when we launch my Google Chrome.
This URL would be added after an explicit user consent.
Thanks for your help.

What is the expected behavior?
Being able to add dynamically an URL to the Google startpages

What went wrong?
Not able to realize that

Did this work before? N/A 

Does this work in other browsers? N/A

Chrome version: 60.0.3112.113  Channel: n/a
OS Version: 10.0
Flash Version: 

Thanks for your help.