message: remove cast and use imported dtypes
diff: @@ -831,7 +831,7 @@ def _QuantizeAndDequantizeV3Grad(_, grad):
  @ops.RegisterGradient("ExtractImagePatches")
  def _ExtractImagePatchesGrad(op, grad):
  - input_bhwc = math_ops.cast(array_ops.shape(op.inputs[0]), ops.dtypes.int64)
  + input_bhwc = array_ops.shape(op.inputs[0], out_type=dtypes.int64)
  batch_size, rows_in, cols_in, channels = input_bhwc[0], input_bhwc[1], \
  input_bhwc[2], input_bhwc[3]
  @@ -850,7 +850,7 @@ def _ExtractImagePatchesGrad(op, grad):
  op.get_attr("padding"))
  # Create indices matrix for output tensor.
  - output_bhwc = math_ops.cast(array_ops.shape(op.outputs[0]), ops.dtypes.int64)
  + output_bhwc = array_ops.shape(op.outputs[0], out_type=dtypes.int64)
  rows_out, cols_out = output_bhwc[1], output_bhwc[2]
  _, ksize_r, ksize_c, _ = op.get_attr("ksizes")
  # Indices for output start from 0.
  