Re: Long Tasks Notifications API

On Fri, Aug 5, 2016 at 3:39 PM Ilya Grigorik <igrigorik@google.com> wrote:

>
> On Fri, Aug 5, 2016 at 3:22 PM, Shubhie Panicker <panicker@google.com>
> wrote:
>
>> - Re: extensions
>> We *may* be able to indicate something generic here. Prior investigation
>> <https://codereview.chromium.org/1615523002/> indicates that it's very
>> difficult to properly account for scripts spawned by extensions.
>>
>
> I think we want to be really careful with this one.. Yes, extensions can
> definitely affect runtime of the page, both in the early stages of the page
> load and while the page is active, and it would be nice to get a handle on
> that. However, we can't simply expose which extensions (e.g. script urls
> and related bits) the user is running due to security/privacy concerns.
>
> It's a problem worth thinking about, but I would mark it as an explicit
> non-goal for the v1 we're discussing here..
>

Speculating a bit, I could imagine a response header for the main resource
that instructs the browser to observe long tasks from the beginning of the
page load and make them available to PerformanceObserver. I think it's
probably a solvable problem, but there's a ton of details to work out, so
definitely not a V1 feature. Also, by the time we get around to trying to
solve this, we may have better general RUM support that Shubhie alluded to
and not need to solve it with this API.