crash log for renderer (pid <unknown>):
STDOUT: <empty>
STDERR: [1:1:0123/130205.389194:FATAL:V0CustomElementRegistrationContext.cpp(161)] Check failed: !V0CustomElement::IsValidName(element->localName()). 
STDERR: #0 0x00000314d1ec base::debug::StackTrace::StackTrace()
STDERR: #1 0x00000316c2c3 logging::LogMessage::~LogMessage()
STDERR: #2 0x00000559ba76 blink::V0CustomElementRegistrationContext::SetTypeExtension()
STDERR: #3 0x0000051171eb blink::Element::CloneAttributesFromElement()
STDERR: #4 0x000005100923 blink::Element::CloneElementWithoutChildren()
STDERR: #5 0x000004a8613a blink::V8Node::cloneNodeMethodCallback()
STDERR: #6 0x000001cc5b32 v8::internal::FunctionCallbackArguments::Call()
STDERR: #7 0x000001da85e5 v8::internal::(anonymous namespace)::HandleApiCallHelper<>()
STDERR: #8 0x000001da66d9 v8::internal::Builtin_Impl_HandleApiCall()
STDERR: #9 0x000001da611d v8::internal::Builtin_HandleApiCall()
STDERR: #10 0x01cfe65043e4 <unknown>
STDERR: 
STDERR: [23396:23527:0123/130205.444136:WARNING:crash_handler_host_linux.cc(330)] Could not translate tid, attempt = 1 retry ...