message: Remove reference to external cache.
diff: @@ -18,7 +18,6 @@ limitations under the License.
  #include "tensorflow/core/platform/status.h"
  #include "tensorflow/core/tpu/kernels/tpu_compilation_cache.pb.h"
  #include "tensorflow/core/tpu/kernels/tpu_compilation_cache_entry.h"
  -#include "tensorflow/core/tpu/kernels/tpu_compilation_cache_external.h"
  #include "tensorflow/core/tpu/kernels/tpu_compilation_cache_interface.h"
  #include "tensorflow/core/tpu/kernels/tpu_compilation_cache_lookup.h"
  