What steps will reproduce the problem?
(1) Go to: chrome-devtools://devtools/bundled/inspector.html
(2) Save page as MHTML, and open result in Chromium

What is the expected result?
Icons should appear in loaded MHTML page

What happens instead?
All icons (3-dot menu, device menu in left corner, settings gears, etc) are blank.
Console error: "Not allowed to load local resource: chrome-devtools://devtools/bundled/Images/smallIcons.png"

It seems other pages with images serialize images into data URLs.  Would it be possible to serialize images whose protocol is from "chrome-devtools://"?