crash log for renderer (pid 17211):
STDOUT: #CRASHED - renderer (pid 17211)
STDERR: ASSERTION FAILED: page->orphaned() || m_magic == magic
STDERR: ../../third_party/WebKit/Source/platform/heap/Heap.h(1481) : void blink::HeapObjectHeader::checkHeader() const
STDERR: 1   0x4ab5841 blink::HeapObjectHeader::checkHeader() const
STDERR: 2   0x4ad02b1 blink::Visitor::checkGCInfo(void const*, blink::GCInfo const*)
STDERR: 3   0x629301e blink::DefaultTraceTrait<blink::MIDIPortMap<blink::MIDIInput>, false>::checkGCInfo(blink::Visitor*, blink::MIDIPortMap<blink::MIDIInput> const*)
STDERR: 4   0x6292e99 blink::TraceTrait<blink::MIDIPortMap<blink::MIDIInput> >::checkGCInfo(blink::Visitor*, blink::MIDIPortMap<blink::MIDIInput> const*)
STDERR: 5   0x6292dd1 void blink::Visitor::mark<blink::MIDIPortMap<blink::MIDIInput> const>(blink::MIDIPortMap<blink::MIDIInput> const*)
STDERR: 6   0x6292d57 void blink::Visitor::trace<blink::MIDIPortMap<blink::MIDIInput> const>(blink::Member<blink::MIDIPortMap<blink::MIDIInput> const> const&)
STDERR: 7   0x6292cd4 blink::MIDIPortMap<blink::MIDIInput>::MapIterator<blink::MIDIPortMap<blink::MIDIInput>::ValueSelector>::trace(blink::Visitor*)
STDERR: 8   0x61981dd blink::TraceTrait<blink::Iterator>::trace(blink::Visitor*, void*)
STDERR: 9   0x4abb058 bool blink::CallbackStack::popAndInvokeCallback<(blink::CallbackInvocationMode)0>(blink::CallbackStack**, blink::Visitor*)
STDERR: 10  0x4aae433 blink::Heap::processMarkingStackEntries(int*)
STDERR: 11  0x4abe604 WTF::FunctionWrapper<void (*)(int*)>::operator()(int*)
STDERR: 12  0x4abe5ab WTF::BoundFunctionImpl<WTF::FunctionWrapper<void (*)(int*)>, void ()(int*)>::operator()()
STDERR: 13  0x46622e7 WTF::Function<void ()>::operator()() const
STDERR: 14  0x4662211 blink::Task::run()
STDERR: 15  0xc259e18 base::internal::RunnableAdapter<void (blink::WebThread::Task::*)()>::Run(blink::WebThread::Task*)
STDERR: 16  0xc259d34 base::internal::InvokeHelper<false, void, base::internal::RunnableAdapter<void (blink::WebThread::Task::*)()>, void (blink::WebThread::Task*)>::MakeItSo(base::internal::RunnableAdapter<void (blink::WebThread::Task::*)()>, blink::WebThread::Task*)
STDERR: 17  0xc259c7e base::internal::Invoker<1, base::internal::BindState<base::internal::RunnableAdapter<void (blink::WebThread::Task::*)()>, void (blink::WebThread::Task*), void (base::internal::OwnedWrapper<blink::WebThread::Task>)>, void ()(blink::WebThread::Task*)>::Run(base::internal::BindStateBase*)
STDERR: 18  0x253daaf base::Callback<void ()>::Run() const
STDERR: 19  0x2556d8a base::debug::TaskAnnotator::RunTask(char const*, char const*, base::PendingTask const&)
STDERR: 20  0x264606e base::MessageLoop::RunTask(base::PendingTask const&)
STDERR: 21  0x2646222 base::MessageLoop::DeferOrRunPendingTask(base::PendingTask const&)
STDERR: 22  0x26464f1 base::MessageLoop::DoWork()
STDERR: 23  0x2516055 base::MessagePumpCFRunLoopBase::RunWork()
STDERR: 24  0x2515471 base::MessagePumpCFRunLoopBase::RunWorkSource(void*)
STDERR: 25  0x98aca04f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
STDERR: 26  0x98ac9a79 __CFRunLoopDoSources0
STDERR: 27  0x98aef826 __CFRunLoopRun
STDERR: 28  0x98aef01a CFRunLoopRunSpecific
STDERR: 29  0x98aeee8b CFRunLoopRunInMode
STDERR: 30  0x2516680 base::MessagePumpCFRunLoop::DoRun(base::MessagePump::Delegate*)
STDERR: 31  0x2515c68 base::MessagePumpCFRunLoopBase::Run(base::MessagePump::Delegate*)