Brave Ads crash when parsing page classifier user model

[tmancey]

https://brave.sp.backtrace.io/p/brave/debug?time=all&filters=(_deleted%3D0%2C(callstack%2Cregex%2C%22(BatAds%7CAdsService%7CAdsImpl%7CConfirmationsImpl)%22)%2C(ver%2Cregex%2C%22(86.1%7C85.1%7C84.1%7C83.1)%22))&fingerprint=0000000000000000000000000000000000000000000000000000000000000201

[00] logging::LogMessage::~LogMessage
[01] base::(anonymous namespace)::OnNoMemory
[02] usermodel::DataPoint::DataPoint
[03] std::__1::__tree_iterator<std::__1::__value_type<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, usermodel::DataPoint>, std::__1::__tree_node<std::__1::__value_type<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, usermodel::DataPoint>, void*>, long> std::__1::__tree<std::__1::__value_type<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, usermodel::DataPoint>, std::__1::__map_value_compare<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, std::__1::__value_type<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, usermodel::DataPoint>, std::__1::less<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator > >, true>, std::__1::allocator<std::__1::__value_type<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, usermodel::DataPoint> > >::__emplace_multi<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator > const, usermodel::DataPoint> const&>
[04] void std::__1::__tree<std::__1::__value_type<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, usermodel::DataPoint>, std::__1::__map_value_compare<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, std::__1::__value_type<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, usermodel::DataPoint>, std::__1::less<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator > >, true>, std::__1::allocator<std::__1::__value_type<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, usermodel::DataPoint> > >::__assign_multi<std::__1::__tree_const_iterator<std::__1::__value_type<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, usermodel::DataPoint>, std::__1::__tree_node<std::__1::__value_type<std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, usermodel::DataPoint>, void>*, long> >
[05] usermodel::Pipeline::FromJson
[06] usermodel::UserModelImpl::InitializePageClassifier
[07] ads::classification::PageClassifier::OnLoadUserModelForId
[08] bat_ads::mojom::BatAdsClient_LoadUserModelForId_ForwardToCallback::Accept
[09] mojo::InterfaceEndpointClient::HandleIncomingMessageThunk::Accept
[10] mojo::internal::MultiplexRouter::ProcessIncomingMessage
[11] mojo::internal::MultiplexRouter::Accept
[12] mojo::Connector::ReadAllAvailableMessages
[13] mojo::SimpleWatcher::OnHandleReady
[14] base::TaskAnnotator::RunTask
[15] base::sequence_manager::internal::ThreadControllerWithMessagePumpImpl::DoWork
[16] base::MessagePumpDefault::Run
[17] base::sequence_manager::internal::ThreadControllerWithMessagePumpImpl::Run
[18] base::RunLoop::Run
[19] content::UtilityMain
[20] content::ContentMainRunnerImpl::Run
[21] service_manager::Main
[22] content::ContentMain
[23] ChromeMain

[tmancey]

@jsecretan This issue occurs when the user disables Brave Ads and the user model component is updated. Setting to P2 as the issue will no longer occur when the user restarts the browser.

This crash just takes down the ads service, which is restarted.

[btlechowski]

Verification passed on

Brave	1.17.59 Chromium: 86.0.4240.183 (Official Build) dev (64-bit)
Revision	0b568b034b8f7994697cb341eeca5979b84151cc-refs/branch-heads/4240@{#1374}
OS	Ubuntu 18.04 LTS

Verified test plan from brave/brave-core#6813
Verified no crash. Verified 3 times.

Verification passed on

Brave	1.17.62 Chromium: 86.0.4240.185 (Official Build) dev (64-bit)
Revision	37e6f852ed18086458552039ad26421aa9fc7acc-refs/branch-heads/4240@{#1377}
OS	Windows 7 Service Pack 1 (Build 7601.24544)

Verified test plan from brave/brave-core#6813
Verified no crash. Verified 7 times.

---

Verified passed with

Brave | 1.17.69 Chromium: 87.0.4280.60 (Official Build) (x86_64)
-- | --
Revision | 12697cfeb273d7de95cf9b18350d2c457f58224c-refs/branch-heads/4280@{#1352}
OS | macOS Version 10.14.6 (Build 18G6042)

Verified test plan from brave/brave-core#6813
No crash observed. Ran thru the test plan 5x.