tree 2729d5422f237d3473a4f43f91e471636cfcc910
parent 7cd27332b38f62294859b53bcf46c0e993ed7896
author Tom McKee <tommckee@chromium.org> 1560905818 -0700
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> 1560906247 -0400

Removing initial Element Timing implicit registration heuristic.

The Element Timing specification originally included a provision for reporting
timings of elements that were automatically detected as 'important'. This would
allow useful information from the Element Timing API to be reported through the
Performance Timeline even if site authors neglected to mark their important
elements with the 'elementtiming' attribute.

The automatic detection of 'important' elements is, necessarily, a heuristic
and, until consensus for the correct heuristic had been reached, we were
treating any image that occupied greater than %15 of the viewport as
'automatically important'. As the Element Timing specification is still being
refined, the exact threshold and heuristic is still being investigated. Until
agreement on an appropriate heuristic is reached, implicit registration will be
disabled.

This CL removes our %15 threshold and disables implicit registration. There was
also WPT coverage to test that all browsers would respect the %15 threshold so
that test is being removed too.

Change-Id: I14847533402f5a68bb3de63a8f9acbd004c5a8e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1643379
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Reviewed-by: Nicolás Peña Moreno <npm@chromium.org>
Commit-Queue: Tom McKee <tommckee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#670319}