I did a one day aggregation on 66 and observed higher count on ContentSecurityPolicy than PageVisits. I suspect there are other features that might behave similarly. 

Other features that have higher count than PageVisists: 
V8SloppyMode, V8StrictMode, SecureContextCheck*, CleanScriptElementWithNonce, HasIDClassTagAttribute

A quick fix to this problem would be not count feature usage until load commit. I am not so sure how doable it is for the features listed above, especially v8 stuff. 

I am also trying to 1. move the UseCounter to the browser side; 2. buffer pre-loading features and send them to the browser side upon load commit, which will fix this problem eventually. 

Pri-0 bugs are critical regressions or serious emergencies, and this bug has not been updated in three days. Could you please provide an update, or adjust the priority to a more appropriate level if applicable?

If a fix is in active development, please set the status to Started.

Thanks for your time! To disable nags, add the Disable-Nags label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Not on the Chrome team anymore. removing from cc

There should no longer be feature usage higher than page visits as the features usecounter has beeen moved to the browser side. However there is still incorrect behaviour in terms of dropping counts for pre-loading features. But that bug is being tracked in another place. 

Closing this bug now.