crash log for renderer (pid 23068):
STDOUT: #CRASHED - renderer (pid 23068)
STDERR: pure virtual method called
STDERR: terminate called without an active exception
STDERR: Received signal 6
STDERR: #0 0x00000082728e base::debug::StackTrace::StackTrace()
STDERR: #1 0x000000826dc7 base::debug::(anonymous namespace)::StackDumpSignalHandler()
STDERR: #2 0x7f4c4bca8340 <unknown>
STDERR: #3 0x7f4c4a47af79 gsignal
STDERR: #4 0x7f4c4a47e388 abort
STDERR: #5 0x7f4c4aa806b5 __gnu_cxx::__verbose_terminate_handler()
STDERR: #6 0x7f4c4aa7e836 <unknown>
STDERR: #7 0x7f4c4aa7e863 std::terminate()
STDERR: #8 0x7f4c4aa7f33f __cxa_pure_virtual
STDERR: #9 0x0000020b46f4 WebCore::DefaultTraceTrait<>::mark()
STDERR: #10 0x0000020b46ad WebCore::TraceTrait<>::mark()
STDERR: #11 0x0000020b4655 WebCore::Visitor::mark<>()
STDERR: #12 0x0000020b44d9 WebCore::Visitor::trace<>()
STDERR: #13 0x0000020b4470 WTF::HashTraits<>::traceInCollection()
STDERR: #14 0x0000020d0ae2 WTF::TraceInCollectionTrait<>::trace()
STDERR: #15 0x0000020d0aad WebCore::CollectionBackingTraceTrait<>::trace()
STDERR: #16 0x0000020d0a66 WTF::TraceInCollectionTrait<>::trace()
STDERR: #17 0x0000020d08fd WebCore::TraceTrait<>::trace()
STDERR: #18 0x000001a0fb29 WebCore::CallbackStack::popAndInvokeCallback()
STDERR: #19 0x000001a10303 WebCore::Heap::popAndInvokeTraceCallback()
STDERR: #20 0x000001a0f055 WebCore::Heap::collectGarbage()
STDERR: #21 0x000001a14e8f WebCore::ThreadHeap<>::outOfLineAllocate()
STDERR: #22 0x000001a14901 WebCore::ThreadHeap<>::allocate()
STDERR: #23 0x0000020d08b7 WebCore::Heap::allocate<>()
STDERR: #24 0x0000020d0805 WebCore::HeapAllocator::malloc<>()
STDERR: #25 0x0000020d07e5 WebCore::HeapAllocator::zeroedBackingMalloc<>()
STDERR: #26 0x0000020d0281 WTF::HashTable<>::allocateTable()
STDERR: #27 0x0000020d00d0 WTF::HashTable<>::rehash()
STDERR: #28 0x0000020d0fe3 WTF::HashTable<>::expand()
STDERR: #29 0x0000020d0ed9 WTF::HashTable<>::add<>()
STDERR: #30 0x0000020d0c1f WTF::HashTable<>::add()
STDERR: #31 0x0000020aab5f WTF::HashSet<>::add()
STDERR: #32 0x00000208d249 WebCore::Document::registerVisibilityObserver()
STDERR: #33 0x00000208cfb0 WebCore::DocumentVisibilityObserver::registerObserver()
STDERR: #34 0x00000208ceda WebCore::DocumentVisibilityObserver::DocumentVisibilityObserver()
STDERR: #35 0x00000239b9f9 WebCore::HTMLCanvasElement::HTMLCanvasElement()
STDERR: #36 0x000002398659 WebCore::HTMLCanvasElement::create()
STDERR: #37 0x00000374d032 WebCore::canvasConstructor()
STDERR: #38 0x00000374c04a WebCore::HTMLElementFactory::createHTMLElement()
STDERR: #39 0x00000208fe6f WebCore::Document::createElement()
STDERR: #40 0x0000035882bd WebCore::DocumentV8Internal::createElement1MethodForMainWorld()
STDERR: #41 0x000003587eb1 WebCore::DocumentV8Internal::createElementMethodForMainWorld()
STDERR: #42 0x000003585474 WebCore::DocumentV8Internal::createElementMethodCallbackForMainWorld()
STDERR: #43 0x000001f618c3 v8::internal::FunctionCallbackArguments::Call()
STDERR: #44 0x000001acec24 v8::internal::Builtin_HandleApiCall()
STDERR: #45 0x01123db066ee <unknown>
STDERR:   r8: 00007f4c4a8059d0  r9: 00007f4c4aadf010 r10: 0000000000000008 r11: 0000000000000206
STDERR:  r12: 000000000a0bf372 r13: 0000000000000000 r14: 0000000003585450 r15: 000000000af72270
STDERR:   di: 0000000000000006  si: 0000000000000006  bp: 00007fff80fdfec0  bx: 0000000000000000
STDERR:   dx: 0000000000000006  ax: 0000000000000000  cx: ffffffffffffffff  sp: 00007fff80fdfd18
STDERR:   ip: 00007f4c4a47af79 efl: 0000000000000206 cgf: 0000000000000033 erf: 0000000000000000
STDERR:  trp: 0000000000000000 msk: 0000000000000000 cr2: 0000000000000000