Posted this in the Google Chrome product forums just a little while ago (grossness warning!):
Can't STOP a built-in manager download in an acceptable way… :-/ (v56, v57-Beta)
Abso-lutely freaking unbelievable! 
Cheers ^:)
I almost died in that note part 
So, do you try to wipe the program data? I dont know how the name in english, in portuguese it called “limpar padrões”
Well, in Android v5.1 it's under “Settings -> Apps” (“Configurar -> Aplicativos” for Brazilian Portuguese).
This is something one does not usually needs to resort to unless some sort of major screwage happens with an app.
A friend asked me to verify the validity of a @#$% thousands of megabytes link, and I did. The thing started to download but
found no way to stop downloading a file for which I didn't have enough phone storage nor I had any interest in downloading. He was having problems starting the download from his computer. Then I also tested another several hundred megabytes video and found the same incomprehensible problem.
All this sort of stuff smells like deliberate official software sabotage. 
Cheers ^:)