[Passwords] Compute User Actions in PasswordFormMetricsRecorder

This change replaces PasswordFormMetricsRecorder's SetUserAction with a
ComputeUserAction API. This allows for removing duplicated code between
the old and new PasswordFormManager and fixes issues with metrics
recording, when both versions of the form manager are active at the same
time.

Bug: 926902
Change-Id: I61373e88d8349fb2e52a5d89ca7b4ec6eda7a305
Reviewed-on: https://chromium-review.googlesource.com/c/1448188
Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#628357}(cherry picked from commit bd56e6922f2f6a7591e68c06d1f3f6470dfb046c)
Reviewed-on: https://chromium-review.googlesource.com/c/1451923
Reviewed-by: Jan Wilken Dörrie <jdoerrie@chromium.org>
Cr-Commit-Position: refs/branch-heads/3683@{#159}
Cr-Branched-From: e51029943e0a38dd794b73caaf6373d5496ae783-refs/heads/master@{#625896}
8 files changed