message: Use BefBuffer instead of AlignedBuffer<8>
  BEFBuffer is renamed as BefBuffer.
  bef_buffer.h, bef_encoding.h, bef_reader.h are relocated to tfrt/bef.
  All AlignedBuffer<8> are changed to BefBuffer.
diff: @@ -19,6 +19,7 @@ limitations under the License.
  #include "tensorflow/core/platform/errors.h"
  #if BEF_THUNKS
  +#include "tfrt/bef/bef_buffer.h"
  #include "tfrt/bef_converter/mlir_to_bef_translate.h"
  #include "tfrt/core_runtime/core_runtime.h"
  #include "tfrt/gpu/gpu_types.h"
  @@ -26,7 +27,6 @@ limitations under the License.
  #include "tfrt/host_context/chain.h"
  #include "tfrt/host_context/execution_context.h"
  #include "tfrt/host_context/host_context.h"
  -#include "tfrt/support/aligned_buffer.h"
  #include "tensorflow/compiler/mlir/tfrt/transforms/lhlo_gpu_to_tfrt_gpu/gpu_passes.h"
  #include "tensorflow/stream_executor/cuda/cuda_driver.h"
  #include "tensorflow/stream_executor/device_memory.h"
  @@ -55,7 +55,7 @@ StatusOr<std::unique_ptr<tfrt::gpu::Program>> ConvertToGpuProgram(
  return tensorflow::errors::Internal("Failed to translate MLIR to BEF.");
  }
  - auto buffer = tfrt::AlignedBuffer<8>(bef.data(), bef.data() + bef.size());
  + auto buffer = tfrt::BefBuffer(bef.data(), bef.data() + bef.size());
  // TODO(hanbinyoon): Programmatically get the function name after b/186927461.
  return absl::make_unique<tfrt::gpu::Program>(std::move(buffer),
  "main_sync_region", host);
  