Looks like a crash in V8/wasm:

Stack Trace:
********************************************************************************
	Last event: c64.fd4: Access violation - code c0000005 (first/second chance not available)
	  debugger time: Thu Oct 11 05:37:03.072 2018 (UTC - 7:00)
	ChildEBP RetAddr  Args to Child              
	04ccec18 6a22a90d 00000016 94b8524a 6a24bd4d chrome_child!base::win::`anonymous namespace'::ForceCrashOnSigAbort
	04ccec6c 683dea30 00000016 04ccee98 683db89f chrome_child!raise+0x1c3
	04ccec78 683db89e decade10 65726e75 61686361 chrome_child!v8::base::OS::Abort+0x30
	04ccee98 67e62a9e 6a246740 00000000 6a24bd4d chrome_child!V8_Fatal+0xce
	04cceef8 67e640f4 fffff5c9 04ccf410 00000008 chrome_child!v8::internal::wasm::LiftoffAssembler::Spill+0x18e
	04ccef44 67e63fe1 04ccef10 04ccef10 94b85146 chrome_child!v8::internal::wasm::LiftoffAssembler::SpillRegister+0xf4
	04ccef60 67e80c1f 04ccefc4 00000007 00000087 chrome_child!v8::internal::wasm::LiftoffAssembler::SpillOneRegister+0x61
	04cceff8 67e6efbc 00000000 00000002 00000000 chrome_child!v8::internal::wasm::LiftoffAssembler::Store+0x2bf
	04ccf134 67e67eba 00000004 00001000 00c24ee4 chrome_child!v8::internal::wasm::WasmFullDecoder<v8::internal::wasm::Decoder::kValidate,v8::internal::wasm::(anonymous namespace)::LiftoffCompiler>::DecodeStoreMem+0x3bc
	04ccf338 67e65950 041def50 041e2d50 0409f288 chrome_child!v8::internal::wasm::WasmFullDecoder<v8::internal::wasm::Decoder::kValidate,v8::internal::wasm::(anonymous namespace)::LiftoffCompiler>::DecodeFunctionBody+0x184a
	04ccf60c 67e92c97 0411c864 00000000 00000000 chrome_child!v8::internal::wasm::LiftoffCompilationUnit::ExecuteCompilation+0x400
	04ccf640 67e99b57 0411c864 0985153c 09857550 chrome_child!v8::internal::wasm::WasmCompilationUnit::ExecuteCompilation+0xb7
	04ccf668 67e9c2dc 0411c864 00c80826 00000000 chrome_child!v8::internal::wasm::`anonymous namespace'::FetchAndExecuteCompilationUnit+0x87
	04ccf684 66c9b77a 072789b8 00000000 0000000f chrome_child!v8::internal::wasm::`anonymous namespace'::BackgroundCompileTask::RunInternal+0x4c
	04ccf6e8 66cf6086 00000000 04ccf7a0 00000000 chrome_child!base::debug::TaskAnnotator::RunTask+0xda
	04ccf798 66cf5d77 00000000 6a5c53e5 6a5c53cc chrome_child!base::internal::TaskTracker::RunOrSkipTask+0x1b6
	04ccf8b0 66c92ee9 04ccf8c4 099ab640 0401a530 chrome_child!base::internal::TaskTracker::RunAndPopNextTask+0xe7
	04ccf90c 66c928dc 000000df 94b8473a 04ccf940 chrome_child!base::internal::SchedulerWorker::RunWorker+0x169
	04ccf91c 680d58b5 040f5550 000002f4 000002f4 chrome_child!base::internal::SchedulerWorker::RunPooledWorker+0x1c
	*** WARNING: Unable to verify checksum for kernel32.dll
	*** ERROR: Symbol file could not be found.  Defaulted to export symbols for kernel32.dll - 
	04ccf940 761b338a 040f5dc8 04ccf98c 771b9a02 chrome_child!base::`anonymous namespace'::ThreadFunc+0x95
	WARNING: Stack unwind information not available. Following frames may be wrong.
	04ccf94c 771b9a02 040f5dc8 72c15a1d 00000000 kernel32!BaseThreadInitThunk+0x12
	04ccf98c 771b99d5 680d5820 040f5dc8 ffffffff ntdll!RtlInitializeExceptionChain+0x63
	04ccf9a4 00000000 680d5820 040f5dc8 00000000 ntdll!RtlInitializeExceptionChain+0x36

Looks like a possible dup of issue 894307, assigning to Clemens.

Should be fixed with https://crrev.com/c/1275819. Will keep an eye on the waterfall.