Cannot reproduce because the debug build crashes on startup. Waiting...

Open chrome/browser/search/thumbnail_source.cc and comment out the lines 53-91.

#2 doesn't help me

Still cannot reproduce the issue. 

Somehow OnLoginSucccessful was triggered on page refresh. I don't see it now.

Vasilii, can you help with repro steps? Has this change hit Canary, yet?

Because on Canary (Mac) 69.0.3451.0 I can't reproduce using the following steps:
- enable password generation from chrome://flags
- relaunch Chrome
- go to facebook.com
- on the sign-up form click into the password field
- confirm generation drop-down shows
- click on the generated password
- confirm the password got filled into the password field
- reload the page

No crash.

This is a DCHECK, it's off by default in the release builds.

I can reproduce it on the top of the tree

[19790:775:0608/105854.284266:FATAL:password_form_manager.cc(158)] Check failed: !form.password_element.empty(). 
0   libbase.dylib                       0x00000001053f50ce base::debug::StackTrace::StackTrace(unsigned long) + 174
1   libbase.dylib                       0x00000001053f518d base::debug::StackTrace::StackTrace(unsigned long) + 29
2   libbase.dylib                       0x000000010501cddc base::debug::StackTrace::StackTrace() + 28
3   libbase.dylib                       0x000000010509bb4c logging::LogMessage::~LogMessage() + 460
4   libbase.dylib                       0x00000001050998b5 logging::LogMessage::~LogMessage() + 21
5   libchrome_dll.dylib                 0x000000010d80704a password_manager::(anonymous namespace)::SetFieldLabelsOnSave(autofill::ServerFieldType, autofill::PasswordForm const&, std::__1::map<std::__1::basic_string<unsigned short, base::string16_internals::string16_char_traits, std::__1::allocator<unsigned short> >, autofill::ServerFieldType, std::__1::less<std::__1::basic_string<unsigned short, base::string16_internals::string16_char_traits, std::__1::allocator<unsigned short> > >, std::__1::allocator<std::__1::pair<std::__1::basic_string<unsigned short, base::string16_internals::string16_char_traits, std::__1::allocator<unsigned short> > const, autofill::ServerFieldType> > >*) + 906
6   libchrome_dll.dylib                 0x000000010d7fd0ca password_manager::PasswordFormManager::UploadPasswordVote(autofill::PasswordForm const&, autofill::ServerFieldType const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) + 1034
7   libchrome_dll.dylib                 0x000000010d803f1b password_manager::PasswordFormManager::SendVoteOnCredentialsReuse(autofill::PasswordForm const&, autofill::PasswordForm*) + 315
8   libchrome_dll.dylib                 0x000000010d7fada4 password_manager::PasswordFormManager::ProcessUpdate() + 836
9   libchrome_dll.dylib                 0x000000010d7f91e2 password_manager::PasswordFormManager::Save() + 850
10  libchrome_dll.dylib                 0x000000010d885daf password_manager::PasswordManager::OnLoginSuccessful() + 3999
11  libchrome_dll.dylib                 0x000000010d88ae1a password_manager::PasswordManager::OnPasswordFormsRendered(password_manager::PasswordManagerDriver*, std::__1::vector<autofill::PasswordForm, std::__1::allocator<autofill::PasswordForm> > const&, bool) + 4538
12  libchrome_dll.dylib                 0x000000010f264260 password_manager::ContentPasswordManagerDriver::PasswordFormsRendered(std::__1::vector<autofill::PasswordForm, std::__1::allocator<autofill::PasswordForm> > const&, bool) + 576

ugh. most. stupid. question. of. the. quarter.

Thanks for reminding me ;).

This DCHECK is not necessary. A field may have an empty name. Then, we shouldn't upload any votes for such forms. It is already checked in |LabelFields|. So, I will simply remove a couple of DCHECKs.

However, it is strange that OnLoginSucessful is triggered without real form submission. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/457bd39091c7293908c7876f3fbefd7dc07701c3

commit 457bd39091c7293908c7876f3fbefd7dc07701c3
Author: Maxim Kolosovskiy <kolos@chromium.org>
Date: Mon Jun 11 15:39:06 2018

[Password Manager] Remove DCHECKs for field name as a field can have
empty name

Votes are not uploaded for fields with empty names. It is checked in |LabelFields|. So, adding empty keys to |field_types| is ok.

Bug:  850013 
Change-Id: I46dd0b665a612d5c23e116d7e2664e5c12d7f804
Reviewed-on: https://chromium-review.googlesource.com/1092855
Commit-Queue: Maxim Kolosovskiy <kolos@chromium.org>
Reviewed-by: Vadym Doroshenko <dvadym@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566011}
[modify] https://crrev.com/457bd39091c7293908c7876f3fbefd7dc07701c3/components/password_manager/core/browser/password_form_manager.cc