Occurs on patch
https://codereview.chromium.org/2820783002/#ps1

This patch replaces all MessageBuilder with MessageV2Builder and builder.encodeStruct with builder.setPayload.

If you change them back to MessageBuilder and builder.encodeStruct in
out/Default/gen/mojo/edk/js/tests/js_to_cpp.mojom.js

JsToCppTest.BitFlip passes, but regardless if the message is V2 or V0. This failure should not happen on the C++ side. Needs investigation.

wangjimmy@wangjimmy0:~/chromium/src$ out/Default/mojo_js_integration_tests --gtest_filter=JsToCppTest.BitFlip
IMPORTANT DEBUGGING NOTE: batches of tests are run inside their
own process. For debugging a test inside a debugger, use the
--gtest_filter=<your_test_name> flag along with
--single-process-tests.
Using sharding settings from environment. This is shard 0/1
Using 1 parallel jobs.
Note: Google Test filter = JsToCppTest.BitFlip
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from JsToCppTest
[ RUN      ] JsToCppTest.BitFlip
Received signal 11 SEGV_MAPERR 000000000008
#0 0x7f3e1aa394eb base::debug::StackTrace::StackTrace()
#1 0x7f3e1aa381ec base::debug::StackTrace::StackTrace()
#2 0x7f3e1aa38fff base::debug::(anonymous namespace)::StackDumpSignalHandler()
#3 0x7f3e1aeb8330 <unknown>
#4 0x00000043623c mojo::internal::DecodePointer()
#5 0x0000004361c5 mojo::internal::Pointer<>::Get()
#6 0x000000431fb4 js_to_cpp::EchoArgsListDataView::ReadNext<>()
#7 0x00000042e698 js_to_cpp::CppSideStubDispatch::Accept()
#8 0x0000004219c3 js_to_cpp::CppSideStub<>::Accept()
#9 0x7f3e1b225bff mojo::InterfaceEndpointClient::HandleValidatedMessage()
#10 0x7f3e1b225551 mojo::InterfaceEndpointClient::HandleIncomingMessageThunk::Accept()
#11 0x7f3e1b223275 mojo::FilterChain::Accept()
#12 0x7f3e1b227691 mojo::InterfaceEndpointClient::HandleIncomingMessage()
#13 0x7f3e1b23d5b1 mojo::internal::MultiplexRouter::ProcessIncomingMessage()
#14 0x7f3e1b23cdbc mojo::internal::MultiplexRouter::Accept()
#15 0x7f3e1b223275 mojo::FilterChain::Accept()
#16 0x7f3e1b21730b mojo::Connector::ReadSingleMessage()
#17 0x7f3e1b218047 mojo::Connector::ReadAllAvailableMessages()
#18 0x7f3e1b217e0e mojo::Connector::OnHandleReadyInternal()
#19 0x7f3e1b217ceb mojo::Connector::OnWatcherHandleReady()
#20 0x7f3e1b21ab7c _ZN4base8internal13FunctorTraitsIMN4mojo9ConnectorEFvjEvE6InvokeIPS3_JjEEEvS5_OT_DpOT0_
#21 0x7f3e1b21aa86 _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKMN4mojo9ConnectorEFvjEJPS5_jEEEvOT_DpOT0_
#22 0x7f3e1b21aa17 _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo9ConnectorEFvjEJNS0_17UnretainedWrapperIS4_EEEEEFvjEE7RunImplIRKS6_RKSt5tupleIJS8_EEJLm0EEEEvOT_OT0_NS_13IndexSequenceIJXspT1_EEEEOj
#23 0x7f3e1b21a91c _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo9ConnectorEFvjEJNS0_17UnretainedWrapperIS4_EEEEEFvjEE3RunEPNS0_13BindStateBaseEOj
#24 0x7f3e1b1bcdd1 _ZNKR4base8CallbackIFvjELNS_8internal8CopyModeE1ELNS2_10RepeatModeE1EE3RunEj
#25 0x7f3e1b1bc176 mojo::SimpleWatcher::OnHandleReady()
#26 0x7f3e1b1bd813 _ZN4base8internal13FunctorTraitsIMN4mojo13SimpleWatcherEFvijEvE6InvokeIRKNS_7WeakPtrIS3_EEJRKiRKjEEEvS5_OT_DpOT0_
#27 0x7f3e1b1bd664 _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKMN4mojo13SimpleWatcherEFvijERKNS_7WeakPtrIS5_EEJRKiRKjEEEvOT_OT0_DpOT1_
#28 0x7f3e1b1bd5c4 _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo13SimpleWatcherEFvijEJNS_7WeakPtrIS4_EEijEEEFvvEE7RunImplIRKS6_RKSt5tupleIJS8_ijEEJLm0ELm1ELm2EEEEvOT_OT0_NS_13IndexSequenceIJXspT1_EEEE
#29 0x7f3e1b1bd46c _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo13SimpleWatcherEFvijEJNS_7WeakPtrIS4_EEijEEEFvvEE3RunEPNS0_13BindStateBaseE
#30 0x7f3e1aa3f9fe _ZNO4base8CallbackIFvvELNS_8internal8CopyModeE0ELNS2_10RepeatModeE0EE3RunEv
#31 0x7f3e1aa3f13e base::debug::TaskAnnotator::RunTask()
#32 0x7f3e1aacf86d base::MessageLoop::RunTask()
#33 0x7f3e1aacfaf4 base::MessageLoop::DeferOrRunPendingTask()
#34 0x7f3e1aacfde4 base::MessageLoop::DoWork()
#35 0x7f3e1aae6f18 base::MessagePumpDefault::Run()
#36 0x7f3e1aacf407 base::MessageLoop::RunHandler()
#37 0x7f3e1ab7237a base::RunLoop::Run()
#38 0x00000041db79 mojo::edk::js::JsToCppTest::RunTest()
#39 0x00000041deee mojo::edk::js::JsToCppTest_BitFlip_Test::TestBody()
#40 0x00000048b26e testing::internal::HandleSehExceptionsInMethodIfSupported<>()
#41 0x000000476c72 testing::internal::HandleExceptionsInMethodIfSupported<>()
#42 0x00000046af46 testing::Test::Run()
#43 0x00000046b6fd testing::TestInfo::Run()
#44 0x00000046bc9f testing::TestCase::Run()
#45 0x00000047100c testing::internal::UnitTestImpl::RunAllTests()
#46 0x00000048fc1e testing::internal::HandleSehExceptionsInMethodIfSupported<>()
#47 0x000000478ad2 testing::internal::HandleExceptionsInMethodIfSupported<>()
#48 0x000000470caf testing::UnitTest::Run()
#49 0x000000497d51 RUN_ALL_TESTS()
#50 0x000000496c62 base::TestSuite::Run()
#51 0x00000043c2b5 _ZN4base8internal13FunctorTraitsIMN2v87IsolateEFvvEvE6InvokeIPS3_JEEEvS5_OT_DpOT0_
#52 0x00000043c1d1 _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKMN2v87IsolateEFvvEJPS5_EEEvOT_DpOT0_
#53 0x000000440497 _ZN4base8internal7InvokerINS0_9BindStateIMNS_9TestSuiteEFivEJNS0_17UnretainedWrapperIS3_EEEEEFivEE7RunImplIRKS5_RKSt5tupleIJS7_EEJLm0EEEEiOT_OT0_NS_13IndexSequenceIJXspT1_EEEE
#54 0x0000004403dc _ZN4base8internal7InvokerINS0_9BindStateIMNS_9TestSuiteEFivEJNS0_17UnretainedWrapperIS3_EEEEEFivEE3RunEPNS0_13BindStateBaseE
#55 0x00000043c91d _ZNKR4base8CallbackIFvvELNS_8internal8CopyModeE1ELNS2_10RepeatModeE1EE3RunEv
#56 0x000000499956 base::(anonymous namespace)::LaunchUnitTestsInternal()
#57 0x0000004997c4 base::LaunchUnitTests()
#58 0x00000044009b main
#59 0x7f3e18d25f45 __libc_start_main
#60 0x00000041d5f9 <unknown>
  r8: 0000000000000000  r9: 00007fffc72e8950 r10: 0000000005f5e102 r11: 0000000000a98aca
 r12: 000000000041d5d0 r13: 00007fffc72edec0 r14: 0000000000000000 r15: 0000000000000000
  di: 0000000000000008  si: 00007fffc72e8eb0  bp: 00007fffc72e8be0  bx: 0000000000000000
  dx: 00007fffc72e8eb0  ax: 00007fffc72e8ec0  cx: 0000000000000000  sp: 00007fffc72e8be0
  ip: 000000000043623c efl: 0000000000010206 cgf: 0000000000000033 erf: 0000000000000004
 trp: 000000000000000e msk: 0000000000000000 cr2: 0000000000000008
[end of stack trace]
Calling _exit(1). Core file will not be generated.
[598:601:0417/152450.734998:757342973663:ERROR:kill_posix.cc(84)] Unable to terminate process group 602: No such process
[1/1] JsToCppTest.BitFlip (CRASHED)
1 test crashed:
    JsToCppTest.BitFlip (../../mojo/edk/js/tests/js_to_cpp_tests.cc:435)
Tests took 5 seconds.