[Telemetry] Add page load ms in baseline ping

[bbinto]

Similar to Focus: https://github.com/mozilla-mobile/focus-android/blob/master/docs/Telemetry.md#page-load-time-histogram Similar to Focus: https://github.com/mozilla-mobile/focus-android/blob/master/docs/Telemetry.md#uri-count

What questions will you answer with this data?

• As a product manager, I want to know if the app renders websites in a timely fashion and if we can see regressions or improvements over time.

Why does Mozilla need to answer these questions? Are there benefits for users? Do we need this information to address product or business requirements?

• Average page load to understand performance and any regressions/improvements on Fenix + GV

What probes (suggested, if applicable)

• page load ms, see row 32 in https://docs.google.com/spreadsheets/d/1P2_aGEE9OtjM3x71d0GBhnHDhzxEL02xEHuKn1no23E/edit#gid=0
• similar to Focus

Dependencies (Added by PM and Eng)

• Core ping / baseline ping

Acceptance Criteria (Added by PM)

• Baseline pings can be queried via re:dash
• We are sending telemetry events for the actions listed in the requirements
• We have documented the telemetry
• We have asked a data steward to review the telemetry
• NOT an AC: Data science to create dashboard or further graphs (this will be a separate issue, this issue is only about hooking up the events described and that they can be queried in re-dash)

┆Issue is synchronized with this Jira Task

[bbinto]

@georgf - does GleanSDK supports histogram/aggregate numbers for this metric?

[bbinto]

Also @cpeterso maybe we should bring this up with the perf team if/how they want this metric and/or if this should be tracked somewhere else.

[cpeterso]

@vickychin says that she is talking to the telemetry team (?) about adding telemetry probes for Fenix page loads. I don't know if that is this GitHub issue or a different conversation.

[bdekoz]

I'm ok with the perf team tracking this here, and yes, this is the same issue we'd discussed in another perf meeting today.

[bbinto]

@bdekoz, @cpeterso and @vickychin

Ok, I'll close this here then since that's a request/requirement for the perf team, if you need the Fenix team to access or track this metric via the Fenix client, please re-open another ticket.