The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/05d8b86a3c01a0998a914009263a74d3a093c533

commit 05d8b86a3c01a0998a914009263a74d3a093c533
Author: Dominic Battre <battre@chromium.org>
Date: Mon Dec 10 23:25:34 2018

Display reasons for failing to fill in password-manager-internals

The PasswordAutofillAgent may be asked to fill credentials into a form but
reject to do that for valid reasons (e.g. the form is in a cross-origin iframe,
the username is prefilled, ...). This CL introduces logging in
chrome://password-manager-internals to simplify debugging these cases.

Bug:  913516 
Change-Id: I87caf33e7f81face7dc478b78d35d78f33783e06
Reviewed-on: https://chromium-review.googlesource.com/c/1369802
Commit-Queue: Dominic Battré <battre@chromium.org>
Reviewed-by: Vadym Doroshenko <dvadym@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615310}
[modify] https://crrev.com/05d8b86a3c01a0998a914009263a74d3a093c533/components/autofill/content/renderer/password_autofill_agent.cc
[modify] https://crrev.com/05d8b86a3c01a0998a914009263a74d3a093c533/components/autofill/core/common/save_password_progress_logger.cc
[modify] https://crrev.com/05d8b86a3c01a0998a914009263a74d3a093c533/components/autofill/core/common/save_password_progress_logger.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/27cb431ed301257f747c0decfe6bc55e1264321c

commit 27cb431ed301257f747c0decfe6bc55e1264321c
Author: Dominic Battre <battre@chromium.org>
Date: Tue Dec 11 18:37:54 2018

Logging improvements for chrome://password-manager-internals

This CL introduces two minor improvements to the data produced in
chrome://password-manager-internals:

1. The renderer ids are printed for new password elements.
2. For forms that are given to the new form parser, the form signature is
   printed. This makes it a bit easier to search for data that belongs
   together.

Bug:  913516 
Change-Id: Ia1392e0b1f70bab6aa5e6348a10946d1c53046e5
Reviewed-on: https://chromium-review.googlesource.com/c/1371812
Commit-Queue: Dominic Battré <battre@chromium.org>
Reviewed-by: Vadym Doroshenko <dvadym@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615601}
[modify] https://crrev.com/27cb431ed301257f747c0decfe6bc55e1264321c/components/autofill/core/common/save_password_progress_logger.cc
[modify] https://crrev.com/27cb431ed301257f747c0decfe6bc55e1264321c/components/autofill/core/common/save_password_progress_logger.h
[modify] https://crrev.com/27cb431ed301257f747c0decfe6bc55e1264321c/components/password_manager/core/browser/browser_save_password_progress_logger.cc