The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e193ab12ad94456257652249fb86f683b455b6e4

commit e193ab12ad94456257652249fb86f683b455b6e4
Author: Roger McFarlane <rogerm@chromium.org>
Date: Thu Nov 22 20:55:07 2018

[autofill] Rich autofill queries behind a flag.

This CL adds rich metadata to Autofill queries for the purpose of
testing autofill field-type prediction models on the autofill server.
This functionality is limited to non-release channels (i.e., Canary
and Dev, but *NOT* Beta or Stable).

When enabled, Chrome will augment the autofill queries with the
plaintext values of the following form and field metadata:

  For the form:
  * id attribute
  * name attribute

  For each field
  * id attribute
  * name attribute
  * control type (i.e., text, tel, select, etc)
  * label
  * aria label
  * aria description
  * class attribute
  * placeholder attribute

This data will be used by the autofill server to predict the types
of each of the form's fields, for testing and evaluation purposes.

TBR: ellyjones@chromium.org
Bug: 898510
Change-Id: I3f7bc9f550e638137b9e2b34c1142932f791e3ef
Reviewed-on: https://chromium-review.googlesource.com/c/1334090
Commit-Queue: Roger McFarlane <rogerm@chromium.org>
Reviewed-by: Fabio Tirelo <ftirelo@chromium.org>
Reviewed-by: Sebastien Seguin-Gagnon <sebsg@chromium.org>
Reviewed-by: Moe Ahmadi <mahmadi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610484}
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/chrome/browser/about_flags.cc
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/chrome/browser/flag-metadata.json
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/chrome/browser/flag_descriptions.cc
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/chrome/browser/flag_descriptions.h
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/chrome/browser/ui/autofill/chrome_autofill_client.cc
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/chrome/browser/ui/autofill/chrome_autofill_client.h
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/BUILD.gn
[add] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/autofill_client.cc
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/autofill_client.h
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/autofill_download_manager.cc
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/autofill_download_manager_unittest.cc
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/autofill_manager.cc
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/autofill_manager.h
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/autofill_manager_unittest.cc
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/form_structure.cc
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/form_structure.h
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/proto/server.proto
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/browser/test_autofill_manager.h
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/common/autofill_features.cc
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/components/autofill/core/common/autofill_features.h
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/ios/chrome/browser/about_flags.mm
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/ios/chrome/browser/ios_chrome_flag_descriptions.cc
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/ios/chrome/browser/ios_chrome_flag_descriptions.h
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/ios/chrome/browser/ui/autofill/BUILD.gn
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/ios/chrome/browser/ui/autofill/chrome_autofill_client_ios.h
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/ios/chrome/browser/ui/autofill/chrome_autofill_client_ios.mm
[modify] https://crrev.com/e193ab12ad94456257652249fb86f683b455b6e4/tools/metrics/histograms/enums.xml