commit dfdde350d09171aa9bf9b44f51790beb99875b12
author Abigail Klein <abigailbklein@google.com> Fri Jan 27 21:03:10 2023
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Fri Jan 27 21:03:10 2023
tree 1e184af4a811cc65bc05f79e0f9c06684e0ad295
parent 15db4291b2d26da78d7edd97b8e3d29663be3484

[Read Anything] Add UKM metrics for Read Anything feature.

This will enable us to track the URLs where users are making the most
use of the Read Anything feature to aid in improving the underlying
models. The UKM source ID of the main frame of the active web contents
is passed from ReadAnythingController to ReadAnythingAppController. It
is passed to the AXTreeDistiller whenever the
ReadAnythingAppController requests distillation, and the
AXTreeDistiller forwards it to the ScreenAIServiceImpl which records
it when distillation completes.

The data flow of the UKM source ID is:
|-----------------------------|
| Browser process             |
|   ReadAnythingController    |
|   ReadAnythingModel         |
|   ReadAnythingPageHandler   |
|---- read_anything.mojom ----|
| Renderer process            |
|   ReadAnythingAppController |
|   AXTreeDistiller           |
|-- screen_ai_service.mojom --|
| Service process             |
|   ScreenAIServiceImpl       |
|-----------------------------|

UKM review doc:
https://docs.google.com/document/d/1bu443hg5ecH8_FwWdRWDv3w27jnX7aDHaMHiSCWhsRI/edit?pli=1&resourcekey=0-suFhHSowozm-dgv8J2D3Pg#heading=h.bahq24lmowo2

Bug: 1266555
Change-Id: I12e94e9a7571ca2d709cf832368e664881e6fb37
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4152798
Reviewed-by: Dominic Farolino <dom@chromium.org>
Reviewed-by: Yue Ru Sun <yrsun@chromium.org>
Commit-Queue: Abigail Klein <abigailbklein@google.com>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Ramin Halavati <rhalavati@chromium.org>
Reviewed-by: Roger McFarlane <rogerm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1098102}