Current implementation of uninstall dialog is over complicated than necessary to handle the life cycle of dialog-view objects. 
According to msw@
A lot of the delegation and coordination should just disappear by creating a simple dialog (like SimpleMessageBoxViews) that just needs strings, icons, and callbacks (or an ACCEPT/CANCEL/CLOSE enum return value).

I have submitted implementation for Arc apps in https://codereview.chromium.org/2529783002/

But I don't have sufficient experience with "extension world" So I would expect someone who is more familiar with extension system could take over this in-depth refactor/clean up.