Chrome Version: 71.0.3578.98
OS: Windows 7, Windows 10

What steps will reproduce the problem?
(1) Open a built-in page (e.g. chrome://settings/ ). 
(2) Enable the High Contrast extension. 

What happens? 
High contrast extension cannot invert color on that page. 

What is proposed?
Built-in pages color should be inverted.  

Note: Currently, built-in pages (like the New Tab page and Settings pages) are unaffected - extensions like "High Extension" are not allowed to modify them, by design (screenshot- https://screenshot.googleplex.com/V0SShv1ZhXC )

This is associated to case 0-0108000024722 on the case portal.