message: Mirroring upstream github FlatBuffers to third_party/flatbuffers
  This contains ~160 PRs/commits from roughly March 2019 to Dec 2019.
diff: @@ -1673,21 +1673,17 @@ class TensorFlowUnsupported : public BaseOperator {
  for (size_t i = 0; i < keys.size(); ++i) {
  const auto key = keys[i].AsKey();
  const auto& value = m[key];
  - // TODO(wvo): hack to make this code compile with 2 different API
  - // versions.
  - // Please remove once OS/internal versions are in sync.
  - // See hardcoded values in the switch below.
  switch (value.GetType()) {
  - case 5: // flexbuffers::FBT_STRING:
  + case flexbuffers::FBT_STRING:
  (*attr)[key].set_s(value.AsString().c_str());
  break;
  - case 1: // flexbuffers::FBT_INT:
  + case flexbuffers::FBT_INT:
  (*attr)[key].set_i(value.AsInt64());
  break;
  - case 3: // flexbuffers::FBT_FLOAT:
  + case flexbuffers::FBT_FLOAT:
  (*attr)[key].set_f(value.AsFloat());
  break;
  - case 26: // flexbuffers::FBT_BOOL:
  + case flexbuffers::FBT_BOOL:
  (*attr)[key].set_b(value.AsBool());
  if (string(key) == "_output_quantized") {
  op->quantized = value.AsBool();
  @@ -1696,7 +1692,7 @@ class TensorFlowUnsupported : public BaseOperator {
  op->support_output_type_float_in_quantized_op = value.AsBool();
  }
  break;
  - case 11: { // flexbuffers::FBT_VECTOR_INT: {
  + case flexbuffers::FBT_VECTOR_INT: {
  auto* list = (*attr)[key].mutable_list();
  const auto& vector = value.AsTypedVector();
  for (size_t i = 0; i < vector.size(); i++) {
  @@ -1704,7 +1700,7 @@ class TensorFlowUnsupported : public BaseOperator {
  }
  break;
  }
  - case 13: { // flexbuffers::FBT_VECTOR_FLOAT: {
  + case flexbuffers::FBT_VECTOR_FLOAT: {
  auto* list = (*attr)[key].mutable_list();
  const auto& vector = value.AsTypedVector();
  for (size_t i = 0; i < vector.size(); i++) {
  @@ -1712,7 +1708,7 @@ class TensorFlowUnsupported : public BaseOperator {
  }
  break;
  }
  - case 15: { // flexbuffers::FBT_VECTOR_STRING: {
  + case 15 /* TO_DO(wvo): flexbuffers::FBT_VECTOR_STRING_DEPRECATED*/: {
  auto* list = (*attr)[key].mutable_list();
  const auto& vector = value.AsTypedVector();
  for (size_t i = 0; i < vector.size(); i++) {
  