This bug will add:

• EH_TIME_TO_FINAL_RESPONSE - This will collect time duration between receiving a 103 response and the final response.
• EH_NUM_OF_HINTS_PER_PAGE - number of 103 responses received for a page load. 0 will mean that a page has not received a 103 response.
• EH_FINAL_RESPONSE - whether the final response was 2xx or any other code.

EH_TIME_TO_FINAL_RESPONSE - This will collect time duration between receiving a 103 response and the final response. This is only collected for 2xx response and only if at least one 103 has been received.
EH_NUM_OF_HINTS_PER_PAGE - number of 103 responses received for a page load. 0 will mean that a page has not received a 103 response. This is only collected for 2xx response.
EH_FINAL_RESPONSE - whether the final response was 2xx or any other code. This is only collected if at least one 103 has been received.

The change also introduced the class EarlyHintsPreloader that will be extended to perform all EarlyHints tasks.

Comment on attachment 9253199 [details]
request_1743630.md

DATA COLLECTION REVIEW RESPONSE:

Is there or will there be documentation that describes the schema for the ultimate data set available publicly, complete and accurate?

Yes.

Is there a control mechanism that allows the user to turn the data collection on and off?

Yes. This collection is Telemetry so can be controlled through Firefox's Preferences.

If the request is for permanent data collection, is there someone who will monitor the data over time?

No. This collection will expire in Firefox 103.

Using the category system of data types on the Mozilla wiki, what collection type of data do the requested measurements fall under?

Category 1, Technical.

Is the data collection request for default-on or default-off?

Default on for all channels.

Does the instrumentation include the addition of any new identifiers?

No.

Is the data collection covered by the existing Firefox privacy notice?

Yes.

Does the data collection use a third-party collection tool?

No.

Result: datareview+

Backed out for causing mochitest failures on browser_103_telemetry.js. CLOSED TREE

Backout link : https://hg.mozilla.org/integration/autoland/rev/260e2362bbc3acecc2df9cc1561de8af348a20a2

Push with failures : https://treeherder.mozilla.org/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception%2Crunnable&revision=6422173e4853ed2cb051c448d7ef60ad65850d78&selectedTaskRun=fS0vXCP2QbaGvQocxIo7_g.0

Link to failure log : https://treeherder.mozilla.org/logviewer?job_id=359983796&repo=autoland&lineNumber=6987

Failure message:
TEST-UNEXPECTED-FAIL | netwerk/test/browser/browser_103_telemetry.js | false == true - JS frame :: chrome://mochitests/content/browser/netwerk/test/browser/browser_103_telemetry.js :: <TOP_LEVEL> :: line 36

Backed out for causing lint failures on browser_103_telemetry.js

Backout link: https://hg.mozilla.org/integration/autoland/rev/0137a793453d851743a59b4e825a93738fdff162
Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&selectedTaskRun=UudS7PfLQB-fhDJm5nSy0g.0&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=7e152131abba237da9b213758d314d5d80cf519c
Failure log: https://treeherder.mozilla.org/logviewer?job_id=361046565&repo=autoland&lineNumber=412
Failure line: TEST-UNEXPECTED-ERROR | /builds/worker/checkouts/gecko/netwerk/test/browser/browser_103_telemetry.js:7 | Use words like 'skip', 'select', 'allow' or 'deny' instead (avoid-blacklist-and-whitelist)

I am just going to fix bug 1744006.

Backed out for causing mochitest failures on browser_103_telemetry.js

Backout link: https://hg.mozilla.org/integration/autoland/rev/78c0299bace5d20ad4f73d09603d05daca04892f

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=8c24d308cf66be53a5815af09b71771a1c657b61&selectedTaskRun=GpZzd-3rQCCQsrR0GgOzSw.1

Failure log: https://treeherder.mozilla.org/logviewer?job_id=361163113&repo=autoland&lineNumber=5255

Failure line: TEST-UNEXPECTED-FAIL | netwerk/test/browser/browser_103_telemetry.js | Should have found an entry for EH_FINAL_RESPONSE at index 2 - false == true - JS frame :: resource://testing-common/TelemetryTestUtils.jsm :: assertHistogram :: line 309

https://hg.mozilla.org/mozilla-central/rev/551f6aa5b3ba