Chrome Version       : canary (65+)
URLs (if applicable) : N/A

With the way the MainPreferences is currently designed, any change that may missing preferences is not handled gracefully and can cause a crash. 

I would like a propose an approach of  unifying the way of changing preference because I think it would be better and safer for users changing preferences. I have attached the diff of the CL in this email. 
    
This CL unifies the way of chaning preference by adding a common method named "changePreference". In this way, the program can tolerate missing prefrence by design, rather than adding a null pointer for some preference

 

Deleted: commit_diff.txt 7.5 KB

commit_diff.txt 7.5 KB View Download