### TPU Enhancements

*   Adds 3D mesh support in TPU configurations ops.
*   Added TPU code for `FTRL` with `multiply_linear_by_lr`.
*   Silently adds a new file system registry at `gstpu`.
*   Support `restartType` in cloud tpu client.
*   Depend on a specific version of google-api-python-client.
*   Fixes apiclient import.

### Tracing and Debugging

  absl::flat_hash_set<std::string> denylisted_mlir_op_names;
  for (auto& entry : denylisted_ops) {
    denylisted_mlir_op_names.insert(TfLiteToMlir(entry));
  }

  DialectRegistry registry;
  MLIRContext context(registry);
  StatusScopedDiagnosticHandler statusHandler(&context,
                                              /*propagate=*/true);

  // Import input_model to a MLIR module

    xla::CompileOnlyClient* client,
    XlaCompiler::CompilationResult* compilation_result) {
  mlir::DialectRegistry registry;
  mlir::RegisterAllTensorFlowDialects(registry);
  mlir::mhlo::registerAllMhloDialects(registry);
  mlir::MLIRContext context(registry);

  mlir::OwningOpRef<mlir::ModuleOp> mlir_module;
  TF_RETURN_IF_ERROR(DeserializeMlirModule(mlir_computation.mlir_module,

class GraphOptPass
    : public mlir::PassWrapper<GraphOptPass,
                               mlir::OperationPass<mlir::ModuleOp>> {
  void getDependentDialects(mlir::DialectRegistry& registry) const override {
    mlir::RegisterAllTensorFlowDialects(registry);
  }

 public:
  MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(GraphOptPass)

  explicit GraphOptPass(std::vector<tensorflow::GraphOptimizationPass*> passes)

    // It is a terrible idea to have local MLIR contexts so we need to
    // register extensions here, again.
    mlir::DialectRegistry registry;
    registry.insert<mlir::func::FuncDialect>();
    mlir::func::registerAllExtensions(registry);
    xla_call_module_context_.appendDialectRegistry(registry);

    auto l = tensorflow::XlaCallModuleLoader::Create(
        &xla_call_module_context_, op.getVersion(), op.getModule().str(),