Steps to reproduce:
1) Install a Debug build
2) Open chrome://signin-internals

[FATAL:shared_resources_data_source.cc(208)] Check failed: it != GetResourcesMap().end(). missing shared resource: polymer/v1_0/paper-button/paper-button.html

Stack Trace:
  RELADDR   FUNCTION
  00049e44  <UNKNOWN>
  000475e3  <UNKNOWN>
  0001d8a5  <UNKNOWN>
  000193f1  <UNKNOWN>
  00017034  <UNKNOWN>
  v------>  base::debug::(anonymous namespace)::DebugBreak()
  00096cb1  base::debug::BreakDebugger()
  000a85ab  logging::LogMessage::~LogMessage()
  00acd95d  content::SharedResourcesDataSource::IsGzipped(std::__ndk1::basic_string<char, std::__ndk1::char_traits<char>, std::__ndk1::allocator<char> > const&) const
  00acf3a5  content::URLDataManagerBackend::StartRequest(net::URLRequest const*, content::URLRequestChromeJob*)
  00ace89b  content::URLRequestChromeJob::StartAsync()
  0008e8dd  base::OnceCallback<void ()>::Run() &&
  000971ad  base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*)
  000ad355  base::internal::IncomingTaskQueue::RunTask(base::PendingTask*)
  000af2eb  base::MessageLoop::RunTask(base::PendingTask*)
  000af5d7  base::MessageLoop::DeferOrRunPendingTask(base::PendingTask)
  000af6ad  base::MessageLoop::DoWork()
  000b1215  base::MessagePumpLibevent::Run(base::MessagePump::Delegate*)
  000af0af  base::MessageLoop::Run(bool)
  000c76e1  base::RunLoop::Run()
  000e8959  base::Thread::Run(base::RunLoop*)
  0085b78d  content::BrowserThreadImpl::IOThreadRun(base::RunLoop*)
  0085b873  content::BrowserThreadImpl::Run(base::RunLoop*)
  000e8c19  base::Thread::ThreadMain()
  000e3f29  base::(anonymous namespace)::ThreadFunc(void*)
  000470b3  <UNKNOWN>
  00019e3d  <UNKNOWN>