message: Changed to use PredictIdentity for control flow ops.
diff: @@ -69,6 +69,12 @@ constexpr char kFusedBatchNorm[] = "FusedBatchNorm";
  constexpr char kFusedBatchNormGrad[] = "FusedBatchNormGrad";
  constexpr char kQuantizedMatMul[] = "QuantizedMatMul";
  constexpr char kQuantizedMatMulV2[] = "QuantizedMatMulV2";
  +// Dynamic control flow ops.
  +constexpr char kSwitch[] = "Switch";
  +constexpr char kMerge[] = "Merge";
  +constexpr char kEnter[] = "Enter";
  +constexpr char kExit[] = "Exit";
  +constexpr char kNextIteration[] = "NextIteration";
  // Persistent ops.
  constexpr char kConst[] = "Const";
  constexpr char kVariable[] = "Variable";
  @@ -281,6 +287,11 @@ OpLevelCostEstimator::OpLevelCostEstimator() {
  {kSqueeze, wrap(&OpLevelCostEstimator::PredictIdentity)},
  {kRecv, wrap(&OpLevelCostEstimator::PredictIdentity)},
  {kSend, wrap(&OpLevelCostEstimator::PredictIdentity)},
  + {kSwitch, wrap(&OpLevelCostEstimator::PredictIdentity)},
  + {kMerge, wrap(&OpLevelCostEstimator::PredictIdentity)},
  + {kEnter, wrap(&OpLevelCostEstimator::PredictIdentity)},
  + {kExit, wrap(&OpLevelCostEstimator::PredictIdentity)},
  + {kNextIteration, wrap(&OpLevelCostEstimator::PredictIdentity)},
  {kRank, wrap(&OpLevelCostEstimator::PredictMetadata)},
  {kShape, wrap(&OpLevelCostEstimator::PredictMetadata)},
  