commit c5014c35cbe6ffe1b86f1146d63bfd9f404bee19
author Lingqi Chi <lingqi@chromium.org> Wed Mar 23 10:11:02 2022
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed Mar 23 10:11:02 2022
tree fc0051e080ee62a78281e57272e081e926f95c26
parent 8802b00292e17e96c16a3659a4d902cdf144ae84

Prerender: Add timer logic for DSE Prerender

To ensure prerendered results are fresh, this CL deletes the unused
prerendered search results after a fixed duration(following search
prefetch setting).

It also adds a metric tracking the duration between:
1. chrome receives the first correct prerender hints
2. user navigates to the search result page.

Besides that, this CL is the first step to make prerender reuse the
prefetched response. See ryansturm@'s comments on the second patchset in
this CL https://crrev.com/c/3459941. So the newly added metric would
also be used to find the best threshold.

This change should not affect the DSE's PrerenderPredictionStatus.
The newly added SearchPrerenderTask plays the role that
search_prerender_handle_ played before this CL. It is responsible for
tracking a started search prerender, and it keeps alive even if the
handle_ is destroyed by the timer. With its help, PrerenderManager can
record the prediction regardless whether a prerender is expired or not.


Bug: 1295170, 1278634
Change-Id: Ie52c245b752d64e1139627579dcd62700aedebed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3495266
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Reviewed-by: Angela Yoeurng <yoangela@chromium.org>
Reviewed-by: Asami Doi <asamidoi@chromium.org>
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Commit-Queue: Lingqi Chi <lingqi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#984254}