commit 694f4357aca90e45168dab088ea4e0a393eddff8
author Arnaud Mandy <arnaud.mandy@intel.com> Thu Sep 22 11:49:05 2022
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> Thu Sep 22 12:09:43 2022
tree 15956eefc3003057055c0475b60e11a28dd8aa35
parent 12eac81d7dfcac38d42d2676665d24c7744fadd8

compute pressure: Replace quantization with pressure states

As described in [1], compute pressure is using pressure states
instead of quantized value of cpuUtilization and bucketing.

This patch is implementing the following:
 - Removing the quantization of cpuUtilization, bucketing
   and instead is replacing cpu_utilization value with a pressure
   state.
 - A timestamp is retrieved and passed to the web API as defined
   in [2]
 - With the removal of quantization schemes, it is now possible to
   register any number of observers without stopping existing ones
   (which was the case when the quantization scheme of a new observer
   was different)
 - Compute pressure disconnect tests have been reduced. Previously
   quantization threshold changes were resetting the
   PressureServiceImpl object. In the new version, adding a new
   observer doesn't reset the PressureServiceImpl object anymore and
   therefore doesn't send new updates to the PressureObserverManager
   instance if the new update is similar to the previous reported one.
 - As mentioned, there is no reset of the PressureServiceImpl, and the
   filtering of similar updates is happening before the
   PressureObserverManager instance. Therefore it is necessary to
   save ´last_reported_update_´ to update newly registered observers
   with the latest reported update, as well as making sure that if the
   backend is ready before the binding, there is a trace of the first
   update before upcoming ones could be filtered if similar.
   ´last_reported_update_´ will be removed whenever the updates
   filtering will be moved to the PressureObserver class as discussed
   in [3].

[1] https://github.com/WICG/compute-pressure/commit/e3da844ddb2a9bf5d8c86ab561f62bf666ed6d27
[2] https://github.com/WICG/compute-pressure/commit/a10b940a9d50fa3cc526d2b888afe6773d706b20
[3] https://github.com/WICG/compute-pressure/issues/121

Bug: 1306803, 1308316
Change-Id: I60dc2a8b789bdc7808e2629d67541cc6755ecbd1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3865537
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Matthew Denton <mpdenton@chromium.org>
Commit-Queue: Arnaud Mandy <arnaud.mandy@intel.com>
Reviewed-by: Raphael Kubo Da Costa <raphael.kubo.da.costa@intel.com>
Reviewed-by: Fr <beaufort.francois@gmail.com>
Cr-Commit-Position: refs/heads/main@{#1050137}