message: Conditionally include tpu_tracer to profiler_backends only for experimental TPU  support.
diff: load("//tensorflow/core/platform:rules_cc.bzl", "cc_library")
  load("//tensorflow/core/platform:build_config_root.bzl", "if_static")
  -load("//tensorflow:tensorflow.bzl", "if_not_android", "tf_cc_test", "tf_cuda_library")
  +load("//tensorflow:tensorflow.bzl", "if_libtpu", "if_not_android", "tf_cc_test", "tf_cuda_library")
  load("//tensorflow:tensorflow.bzl", "filegroup")
  load(
  "//tensorflow/core/profiler/builds:build_config.bzl",
  @@ -120,7 +120,7 @@ tf_cuda_library(
  visibility = ["//tensorflow:internal"],
  deps = [
  "//tensorflow/core/profiler/internal/cpu:host_tracer",
  - ],
  + ] + if_libtpu(["//tensorflow/core/profiler/internal/tpu:tpu_tracer"]),
  alwayslink = True,
  )
  