commit 7c70a75e2c0963cfa81f623f4594eca39b3b57b9
author Luc Nguyen <lucnguyen@google.com> Thu Jun 02 19:49:09 2022
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Thu Jun 02 19:49:09 2022
tree a8d134b9289d73d270160c5026195efc5be707ef
parent 3635066596520e52b66be7be277985602ced2e25

Reuse provisional client ID until consent is known

This CL persists the provisional client ID across first runs. For
example, a client may quit during the FRE before UMA acceptance. If they re-open Chrome, they will re-use the same provisional client ID when the first run is restarted.

In this CL, we store the provisional client ID in a pref, and is only generated for Chrome-branded builds. This is because Chromium has no metrics reporting.

The provisional client ID pref is cleared when:

1) Promoting the provisional client ID to the client ID (i.e., user enabled metrics reporting) in `MetricsStateManager::ForceClientIdCreation`

2) Disabling UMA reporting (e.g. user does not consent to metrics reporting in the FRE). This is a trickier case, since different platforms may use different path.
- For Chrome browser (Android, Linux, Mac, Windows) and for ChromeOS, this is done in chrome/browser/metrics/metrics_reporting_state.cc.
- On iOS, since we cannot use code under //chrome, this is done in ios/chrome/app/application_delegate/metrics_mediator.mm, which is a "copy" of metrics_reporting_state.cc, but for iOS.
- For WebView/WebLayer, this is done in components/embedder_support/android/metrics/android_metrics_service_client.cc.
- For ChromeCast, there is no need to do it since a client ID is always created: https://source.chromium.org/chromium/chromium/src/+/main:chromecast/metrics/cast_metrics_service_client.cc;l=342;drc=cfd2f377441ba74f5bdf312fbfd1425c29a1b3e5

Bug: 1326569
Change-Id: I96e078c74937f852d36c12ea232e8aece4bf3240
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3634619
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Commit-Queue: Luc Nguyen <lucnguyen@google.com>
Cr-Commit-Position: refs/heads/main@{#1010237}